Class 12 Biology Ecosystem Important Questions and Answers
Structure, productivity, decomposition, pyramids.
Practice questions aligned to NCERT topics used in CBSE classrooms. These are original exam-oriented questions for revision — not official CBSE board papers and not a guarantee of any exam question. Always match the textbook issued by your school and the latest PDFs on ncert.nic.in and cbseacademic.nic.in.
Answers opened: 0
1. Chapter introduction
Ecosystem is Chapter 12 in Class 12 Biology (NCERT Biology). Read the textbook first, then use the 100 questions below as revision — not as a substitute for NCERT examples.
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. CBSE often tests a concept by asking a daily-life example from the same chapter
B. Pyramids of number, biomass, energy
C. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
D. GPP, NPP
Answer
D. GPP, NPP
Explanation
GPP, NPP. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q2MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. 10% law
B. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
C. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
D. Nutrient cycling: carbon, phosphorus
Answer
A. 10% law
Explanation
10% law. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q3MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. Ecological succession if retained
B. Pyramids of number, biomass, energy
C. Every chapter ends with keywords or a summary that is useful for one-mark answers
D. Write three points from Ecosystem in your own words; that is enough for a short-answer start
Answer
B. Pyramids of number, biomass, energy
Explanation
Pyramids of number, biomass, energy. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q4MCQ1 markEasy
Choose the correct statement related to Nutrient cycling in the chapter Ecosystem.
A. Nutrient cycling: carbon, phosphorus
B. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
C. Use the terms used in the NCERT book; do not replace them with unofficial names
D. CBSE often tests a concept by asking a daily-life example from the same chapter
Answer
A. Nutrient cycling: carbon, phosphorus
Explanation
Nutrient cycling: carbon, phosphorus. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q5MCQ1 markModerateRevision pick
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem
B. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
C. Ecological succession if retained
D. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
Answer
C. Ecological succession if retained
Explanation
Ecological succession if retained. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q6MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. Write three points from Ecosystem in your own words; that is enough for a short-answer start
B. Nutrient cycling: carbon, phosphorus
C. Every chapter ends with keywords or a summary that is useful for one-mark answers
D. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
Answer
D. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
Explanation
Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q7MCQ1 markEasy
Choose the correct statement related to Textbook first in the chapter Ecosystem.
A. The textbook says the opposite of this statement
B. CBSE often tests a concept by asking a daily-life example from the same chapter
C. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
D. Use the terms used in the NCERT book; do not replace them with unofficial names
Answer
C. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
Explanation
Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q8MCQ1 markEasy
Choose the correct statement related to Keywords in the chapter Ecosystem.
A. This happens only in a laboratory and never in daily life
B. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem
C. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
D. Every chapter ends with keywords or a summary that is useful for one-mark answers
Answer
D. Every chapter ends with keywords or a summary that is useful for one-mark answers
Explanation
Every chapter ends with keywords or a summary that is useful for one-mark answers. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q9MCQ1 markEasyRevision pick
Choose the correct statement related to Examples in the chapter Ecosystem.
A. Write three points from Ecosystem in your own words; that is enough for a short-answer start
B. This idea is not part of the NCERT chapter
C. CBSE often tests a concept by asking a daily-life example from the same chapter
D. GPP, NPP
Answer
C. CBSE often tests a concept by asking a daily-life example from the same chapter
Explanation
CBSE often tests a concept by asking a daily-life example from the same chapter. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q10MCQ1 markModerate
Choose the correct statement related to Diagrams in the chapter Ecosystem.
A. Use the terms used in the NCERT book; do not replace them with unofficial names
B. The textbook says the opposite of this statement
C. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
D. 10% law
Answer
C. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
Explanation
If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q11MCQ1 markEasy
Choose the correct statement related to Revision in the chapter Ecosystem.
A. Write three points from Ecosystem in your own words; that is enough for a short-answer start
B. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem
C. Pyramids of number, biomass, energy
D. This happens only in a laboratory and never in daily life
Answer
A. Write three points from Ecosystem in your own words; that is enough for a short-answer start
Explanation
Write three points from Ecosystem in your own words; that is enough for a short-answer start. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q12MCQ1 markEasy
Choose the correct statement related to Accuracy in the chapter Ecosystem.
A. Nutrient cycling: carbon, phosphorus
B. This idea is not part of the NCERT chapter
C. Use the terms used in the NCERT book; do not replace them with unofficial names
D. GPP, NPP
Answer
C. Use the terms used in the NCERT book; do not replace them with unofficial names
Explanation
Use the terms used in the NCERT book; do not replace them with unofficial names. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q13MCQ1 markEasyRevision pick
Choose the correct statement related to Practice in the chapter Ecosystem.
A. 10% law
B. Ecological succession if retained
C. The textbook says the opposite of this statement
D. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem
Answer
D. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem
Explanation
Mix MCQs with short answers so you remember both facts and explanations from Ecosystem. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q14MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
B. This happens only in a laboratory and never in daily life
C. Nutrient cycling: carbon, phosphorus
D. GPP, NPP
Answer
D. GPP, NPP
Explanation
GPP, NPP. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q15MCQ1 markModerate
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. Ecological succession if retained
B. 10% law
C. Every chapter ends with keywords or a summary that is useful for one-mark answers
D. GPP, NPP
Answer
B. 10% law
Explanation
10% law. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q16MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. CBSE often tests a concept by asking a daily-life example from the same chapter
B. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
C. Pyramids of number, biomass, energy
D. 10% law
Answer
C. Pyramids of number, biomass, energy
Explanation
Pyramids of number, biomass, energy. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q17MCQ1 markEasyRevision pick
Choose the correct statement related to Nutrient cycling in the chapter Ecosystem.
A. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
B. Pyramids of number, biomass, energy
C. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
D. Nutrient cycling: carbon, phosphorus
Answer
D. Nutrient cycling: carbon, phosphorus
Explanation
Nutrient cycling: carbon, phosphorus. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q18MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. Ecological succession if retained
B. Nutrient cycling: carbon, phosphorus
C. Every chapter ends with keywords or a summary that is useful for one-mark answers
D. Write three points from Ecosystem in your own words; that is enough for a short-answer start
Answer
A. Ecological succession if retained
Explanation
Ecological succession if retained. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q19MCQ1 markEasy
Choose the correct statement related to Ecosystem in the chapter Ecosystem.
A. 10% law
B. Ecological succession if retained
C. This topic is only for college
D. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
Answer
D. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
Explanation
Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q20MCQ1 markModerate
Choose the correct statement related to Textbook first in the chapter Ecosystem.
A. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
B. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology
C. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem
D. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures
Answer
A. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions
Explanation
Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions. The other options mix ideas from nearby topics or reverse the textbook fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q211 Mark1 markEasy
Define or state: Keywords.
Answer
Every chapter ends with keywords or a summary that is useful for one-mark answers.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q221 Mark1 markEasy
Define or state: Examples.
Answer
CBSE often tests a concept by asking a daily-life example from the same chapter.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q231 Mark1 markEasy
Define or state: Diagrams.
Answer
If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q241 Mark1 markEasy
Define or state: Revision.
Answer
Write three points from Ecosystem in your own words; that is enough for a short-answer start.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q251 Mark1 markModerate
Define or state: Accuracy.
Answer
Use the terms used in the NCERT book; do not replace them with unofficial names.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q261 Mark1 markEasy
Define or state: Practice.
Answer
Mix MCQs with short answers so you remember both facts and explanations from Ecosystem.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q271 Mark1 markEasy
Define or state: Ecosystem.
Answer
GPP, NPP.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q281 Mark1 markEasy
Define or state: Ecosystem.
Answer
10% law.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q291 Mark1 markEasy
Define or state: Ecosystem.
Answer
Pyramids of number, biomass, energy.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q301 Mark1 markModerate
Define or state: Nutrient cycling.
Answer
Nutrient cycling: carbon, phosphorus.
Explanation
A one-mark answer should use the textbook term and one clear fact — not a long paragraph.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q312 Mark2 marksModerate
Give two points to explain Ecosystem as used in Ecosystem.
Answer
1. Ecological succession if retained.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q322 Mark2 marksDifficult
Give two points to explain Ecosystem as used in Ecosystem.
Answer
1. Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q332 Mark2 marksModerate
Give two points to explain Textbook first as used in Ecosystem.
Answer
1. Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q342 Mark2 marksModerate
Give two points to explain Keywords as used in Ecosystem.
Answer
1. Every chapter ends with keywords or a summary that is useful for one-mark answers.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q352 Mark2 marksModerate
Give two points to explain Examples as used in Ecosystem.
Answer
1. CBSE often tests a concept by asking a daily-life example from the same chapter.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q362 Mark2 marksDifficult
Give two points to explain Diagrams as used in Ecosystem.
Answer
1. If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q372 Mark2 marksModerate
Give two points to explain Revision as used in Ecosystem.
Answer
1. Write three points from Ecosystem in your own words; that is enough for a short-answer start.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q382 Mark2 marksModerate
Give two points to explain Accuracy as used in Ecosystem.
Answer
1. Use the terms used in the NCERT book; do not replace them with unofficial names.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q392 Mark2 marksModerate
Give two points to explain Practice as used in Ecosystem.
Answer
1. Mix MCQs with short answers so you remember both facts and explanations from Ecosystem.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q402 Mark2 marksDifficult
Give two points to explain Ecosystem as used in Ecosystem.
Answer
1. GPP, NPP.
2. Keep the NCERT wording and add one daily-life example from the same chapter.
Explanation
Two-mark answers work best as two numbered points. One definition plus one example is usually enough.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q413 Mark3 marksModerateRevision pick
Explain Ecosystem in about three points, with one example.
Answer
10% law. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q423 Mark3 marksModerate
Explain Ecosystem in about three points, with one example.
Answer
Pyramids of number, biomass, energy. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q433 Mark3 marksModerate
Explain Nutrient cycling in about three points, with one example.
Answer
Nutrient cycling: carbon, phosphorus. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q443 Mark3 marksDifficult
Explain Ecosystem in about three points, with one example.
Answer
Ecological succession if retained. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q453 Mark3 marksModerateRevision pick
Explain Ecosystem in about three points, with one example.
Answer
Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q463 Mark3 marksModerate
Explain Textbook first in about three points, with one example.
Answer
Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q473 Mark3 marksModerate
Explain Keywords in about three points, with one example.
Answer
Every chapter ends with keywords or a summary that is useful for one-mark answers. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q483 Mark3 marksDifficult
Explain Examples in about three points, with one example.
Answer
CBSE often tests a concept by asking a daily-life example from the same chapter. Example: Use a situation from the NCERT activity or a labelled diagram in this chapter.
Explanation
Three-mark questions want a short explanation, not a full essay. Link the idea to a figure or an activity.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q494 Mark4 marksModerate
Write a long answer on Diagrams. Include definition, explanation and one application.
Answer
Diagrams — If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q504 Mark4 marksModerate
Write a long answer on Revision. Include definition, explanation and one application.
Answer
Revision — Write three points from Ecosystem in your own words; that is enough for a short-answer start. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q514 Mark4 marksModerate
Write a long answer on Accuracy. Include definition, explanation and one application.
Answer
Accuracy — Use the terms used in the NCERT book; do not replace them with unofficial names. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q524 Mark4 marksDifficult
Write a long answer on Practice. Include definition, explanation and one application.
Answer
Practice — Mix MCQs with short answers so you remember both facts and explanations from Ecosystem. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q534 Mark4 marksModerate
Write a long answer on Ecosystem. Include definition, explanation and one application.
Answer
Ecosystem — GPP, NPP. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q544 Mark4 marksModerate
Write a long answer on Ecosystem. Include definition, explanation and one application.
Answer
Ecosystem — 10% law. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q555 Mark5 marksModerate
Write a long answer on Ecosystem. Include definition, explanation and one application.
Answer
Ecosystem — Pyramids of number, biomass, energy. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q565 Mark5 marksModerate
Write a long answer on Nutrient cycling. Include definition, explanation and one application.
Answer
Nutrient cycling — Nutrient cycling: carbon, phosphorus. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q575 Mark5 marksDifficultRevision pick
Write a long answer on Ecosystem. Include definition, explanation and one application.
Answer
Ecosystem — Ecological succession if retained. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q585 Mark5 marksModerate
Write a long answer on Ecosystem. Include definition, explanation and one application.
Answer
Ecosystem — Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q595 Mark5 marksModerate
Write a long answer on Textbook first. Include definition, explanation and one application.
Answer
Textbook first — Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q605 Mark5 marksDifficult
Write a long answer on Keywords. Include definition, explanation and one application.
Answer
Keywords — Every chapter ends with keywords or a summary that is useful for one-mark answers. Explain the idea in order (definition → working → result). End with one application from daily life or a numerical/diagram if the chapter has one.
Explanation
Long answers are marked for structure. Use headings or numbered steps so the examiner can see each part.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q61Assertion and Reason1 markModerate
Assertion (A): CBSE often tests a concept by asking a daily-life example from the same chapter.
Reason (R): Examples is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q62Assertion and Reason1 markModerate
Assertion (A): If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures.
Reason (R): Diagrams is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q63Assertion and Reason1 markModerate
Assertion (A): Write three points from Ecosystem in your own words; that is enough for a short-answer start.
Reason (R): Revision is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q64Assertion and Reason1 markDifficult
Assertion (A): Use the terms used in the NCERT book; do not replace them with unofficial names.
Reason (R): Accuracy is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q65Assertion and Reason1 markModerate
Assertion (A): Mix MCQs with short answers so you remember both facts and explanations from Ecosystem.
Reason (R): Practice is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q66Assertion and Reason1 markModerate
Assertion (A): GPP, NPP.
Reason (R): Ecosystem is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q67Assertion and Reason1 markModerate
Assertion (A): 10% law.
Reason (R): Ecosystem is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q68Assertion and Reason1 markDifficult
Assertion (A): Pyramids of number, biomass, energy.
Reason (R): Ecosystem is a key idea in the chapter Ecosystem.
Choose the correct option.
A. Both A and R are true, and R is the correct explanation of A.
B. Both A and R are true, and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
Answer
A. Both A and R are true, and R is the correct explanation of A.
Explanation
Read Assertion and Reason separately first. Here both match the textbook idea, and R explains why A is taught in this chapter.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q69Case Based4 marksModerateRevision pick
A student is revising Ecosystem and notes: “Nutrient cycling: carbon, phosphorus.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Nutrient cycling.
(ii) Nutrient cycling: carbon, phosphorus.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q70Case Based4 marksModerate
A student is revising Ecosystem and notes: “Ecological succession if retained.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Ecosystem.
(ii) Ecological succession if retained.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q71Case Based4 marksModerate
A student is revising Ecosystem and notes: “Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Ecosystem.
(ii) Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q72Case Based4 marksDifficult
A student is revising Ecosystem and notes: “Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Textbook first.
(ii) Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q73Case Based4 marksModerateRevision pick
A student is revising Ecosystem and notes: “Every chapter ends with keywords or a summary that is useful for one-mark answers.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Keywords.
(ii) Every chapter ends with keywords or a summary that is useful for one-mark answers.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q74Case Based4 marksModerate
A student is revising Ecosystem and notes: “CBSE often tests a concept by asking a daily-life example from the same chapter.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Examples.
(ii) CBSE often tests a concept by asking a daily-life example from the same chapter.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q75Case Based4 marksModerate
A student is revising Ecosystem and notes: “If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Diagrams.
(ii) If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q76Case Based4 marksDifficult
A student is revising Ecosystem and notes: “Write three points from Ecosystem in your own words; that is enough for a short-answer start.” Using this case, answer: (i) Name the idea. (ii) State it in your own words. (iii) Give one classroom or daily-life use.
Answer
(i) Revision.
(ii) Write three points from Ecosystem in your own words; that is enough for a short-answer start.
(iii) Apply it in a school experiment, a labelled diagram, or a situation described in the NCERT chapter.
Explanation
Case-based items recycle a short story. Pull the fact out first, then apply it. This is original practice in CBSE case style — not a copied board paper.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q77Competency Based3 marksModerateRevision pick
Competency practice: A classmate can recall the heading Accuracy but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Use the terms used in the NCERT book; do not replace them with unofficial names. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q78Competency Based3 marksDifficult
Competency practice: A classmate can recall the heading Practice but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Mix MCQs with short answers so you remember both facts and explanations from Ecosystem. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q79Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Ecosystem but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — GPP, NPP. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q80Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Ecosystem but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — 10% law. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q81Competency Based3 marksDifficultRevision pick
Competency practice: A classmate can recall the heading Ecosystem but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Pyramids of number, biomass, energy. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q82Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Nutrient cycling but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Nutrient cycling: carbon, phosphorus. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q83Competency Based3 marksModerate
Competency practice: A classmate can recall the heading Ecosystem but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Ecological succession if retained. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q84Competency Based3 marksDifficult
Competency practice: A classmate can recall the heading Ecosystem but cannot explain it. How will you teach it in two steps using the textbook idea?
Answer
Step 1: State the fact — Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology. Step 2: Show one example or diagram from the chapter and ask the classmate to repeat it in their own words.
Explanation
Competency-based items check whether you can use a concept, not only name it. Teach-back is a simple way to prove understanding.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q85Application Based3 marksModerate
Apply the idea of Textbook first to a real situation you might meet in school or daily life.
Answer
Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q86Application Based3 marksModerate
Apply the idea of Keywords to a real situation you might meet in school or daily life.
Answer
Every chapter ends with keywords or a summary that is useful for one-mark answers. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q87Application Based3 marksModerate
Apply the idea of Examples to a real situation you might meet in school or daily life.
Answer
CBSE often tests a concept by asking a daily-life example from the same chapter. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q88Application Based3 marksDifficult
Apply the idea of Diagrams to a real situation you might meet in school or daily life.
Answer
If the chapter has a diagram, practise labelling it — many school tests ask for labelled figures. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q89Application Based3 marksModerate
Apply the idea of Revision to a real situation you might meet in school or daily life.
Answer
Write three points from Ecosystem in your own words; that is enough for a short-answer start. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q90Application Based3 marksModerate
Apply the idea of Accuracy to a real situation you might meet in school or daily life.
Answer
Use the terms used in the NCERT book; do not replace them with unofficial names. Use this fact to explain a real object, habit, experiment or measurement from the chapter.
Explanation
Application questions reward a specific situation. Name the place (kitchen, playground, lab) and connect it to the fact.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q91HOTS3 marksModerate
HOTS: If someone ignored the idea “Mix MCQs with short answers so you remember both facts and explanations from Ecosystem”, what mistake could they make while solving a question from Ecosystem?
Answer
They would use the wrong term or the reverse relation. Remember: Mix MCQs with short answers so you remember both facts and explanations from Ecosystem. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q92HOTS3 marksModerate
HOTS: If someone ignored the idea “GPP, NPP”, what mistake could they make while solving a question from Ecosystem?
Answer
They would use the wrong term or the reverse relation. Remember: GPP, NPP. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q93HOTS3 marksDifficultRevision pick
HOTS: If someone ignored the idea “10% law”, what mistake could they make while solving a question from Ecosystem?
Answer
They would use the wrong term or the reverse relation. Remember: 10% law. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q94HOTS3 marksModerate
HOTS: If someone ignored the idea “Pyramids of number, biomass, energy”, what mistake could they make while solving a question from Ecosystem?
Answer
They would use the wrong term or the reverse relation. Remember: Pyramids of number, biomass, energy. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q95HOTS3 marksModerate
HOTS: If someone ignored the idea “Nutrient cycling: carbon, phosphorus”, what mistake could they make while solving a question from Ecosystem?
Answer
They would use the wrong term or the reverse relation. Remember: Nutrient cycling: carbon, phosphorus. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q96HOTS3 marksDifficult
HOTS: If someone ignored the idea “Ecological succession if retained”, what mistake could they make while solving a question from Ecosystem?
Answer
They would use the wrong term or the reverse relation. Remember: Ecological succession if retained. Always check the NCERT definition before jumping to a formula or a long explanation.
Explanation
HOTS items ask you to predict an error. That is still chapter revision — not a claim that this exact wording will appear in the board exam.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q97NCERT-style2 marksModerate
NCERT-style exercise: In your own words, write what the chapter teaches about Ecosystem.
Answer
Ecosystem is an NCERT chapter taught in CBSE Class 12 Biology. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q98NCERT-style2 marksModerate
NCERT-style exercise: In your own words, write what the chapter teaches about Textbook first.
Answer
Read the definitions, diagrams and solved examples in the NCERT textbook before practising extra questions. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q99NCERT-style2 marksModerate
NCERT-style exercise: In your own words, write what the chapter teaches about Keywords.
Answer
Every chapter ends with keywords or a summary that is useful for one-mark answers. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
Q100NCERT-style2 marksDifficult
NCERT-style exercise: In your own words, write what the chapter teaches about Examples.
Answer
CBSE often tests a concept by asking a daily-life example from the same chapter. Keep the answer as short as the in-text questions in the textbook.
Explanation
This is original practice in the style of NCERT in-text/exercise questions. It is not copied from any solutions website.
Meta
Class: Class 12 · Subject: Biology · Chapter: Ecosystem · Original GKSchools practice (NCERT-aligned, not an official CBSE paper).
22. Quick revision
Close the answers. Recite three concepts from the list. Then retry ten MCQs and one long answer. That loop is enough for a school test night.
FAQs
Are these official CBSE board questions?
No. They are original practice questions aligned to NCERT topics used in CBSE classrooms. Official sample papers are published on cbseacademic.nic.in.
Will these questions appear in the board exam?
Nobody can promise a question. Use them for revision of frequently tested concepts and exam-style practice.
Is the chapter list the latest NCERT list?
Yes, the catalog follows current NCERT textbooks used in CBSE schools (including new middle-stage books such as Ganita Prakash and Curiosity). Always match the book issued by your school.
How should I use the 100 questions?
Try the question first, then tap Show answer. Mix MCQs with long answers. Revise formulas and diagrams from the textbook alongside this set.
Where are NCERT solutions?
Open the NCERT-style practice link on this subject or chapter. For word-for-word textbook exercise answers, use the NCERT book itself; we do not copy solution keys from other websites.
What is the suggested URL pattern?
Hub /cbse/, then /cbse/class-12/, then subject and chapter slugs.
