Class 12 Biology — Chapter 11: Organisms and Populations
90 practice questions · 30 Easy · 30 Medium · 30 Hard
Practise Class 12 Biology Chapter 11, "Organisms and Populations", with 90 NCERT-aligned multiple-choice questions. The set is split into 30 Easy, 30 Medium and 30 Hard questions, so you can warm up on the fundamentals and then push into the exam-level problems that separate top scorers in CBSE Board exams and NEET UG.
"Organisms and Populations" is one of the chapters where diagram-based recall, terminology and NCERT line-by-line accuracy really pays off. Each MCQ on this chapter is timed and uses exam-grade marking (+2 correct, −1 wrong, 0 skipped), training the same accuracy-under-pressure that real papers demand. Every question carries a short explanation, so a wrong answer becomes a quick lesson rather than a dead end — the fastest way to close gaps before a test.
Use this chapter as targeted revision: attempt the Easy set first to confirm your basics on Organisms and Populations, then move to Medium and Hard to test application and problem-solving. Your accuracy, streaks and XP save automatically, and the chapter feeds into your overall Class 12 Biology mastery score. A few sample questions are shown below; sign in free to practise all 90.
Key concepts: Organisms and Populations (Class 12 Biology)
This chapter covers how organisms respond to their environment, population attributes, growth models, and types of population interactions.
- Responses to abiotic factors
- Organisms cope by regulating, conforming, migrating or suspending activity (e.g. hibernation) in response to temperature, water, light.
- Population attributes
- Birth rate, death rate, sex ratio, age pyramids and population density characterise a population (unlike an individual).
- Population growth models
- Exponential growth (unlimited resources, J-shaped) and logistic growth (limited resources, S-shaped) bounded by carrying capacity K.
- Carrying capacity
- The maximum population size the environment can sustain; logistic growth levels off at K.
- Population interactions
- Mutualism (+/+), competition (−/−), predation and parasitism (+/−), commensalism (+/0) and amensalism (−/0).
Key formulas — Organisms and Populations
💡 Exam tips for Organisms and Populations
- Learn the +/− sign notation for each interaction type — examiners ask you to classify examples.
- Logistic (S-shaped) growth is more realistic than exponential because resources are limited (carrying capacity K).
Sample questions
Both species benefit:
e.g., bees and flowers.
Logistic growth has:
Limits at K (carrying capacity).
Gause's competitive exclusion principle:
One eventually outcompetes.
Organisms and Populations — FAQs
What are the key concepts in Class 12 Biology Organisms and Populations?+
This chapter covers how organisms respond to their environment, population attributes, growth models, and types of population interactions. Key ideas include Responses to abiotic factors, Population attributes, Population growth models, Carrying capacity, Population interactions.
What does Class 12 Biology Chapter 11 (Organisms and Populations) cover on XamBaaz?+
It covers 90 NCERT-aligned MCQs on "Organisms and Populations" — 30 Easy, 30 Medium and 30 Hard — each with a timed quiz and an instant explanation, suitable for CBSE Board exams and NEET UG.
Are these "Organisms and Populations" questions free to practise?+
Yes — sign in with Google to practise "Organisms and Populations" free. Full unlimited access is ₹999/year (limited-time launch price), with no per-chapter charges.
How should I revise "Organisms and Populations" for the exam?+
Start with the Easy quiz to confirm your fundamentals, then attempt Medium and Hard for application-level practice. Review each explanation, retry the questions you miss, and track your accuracy on this chapter until it is consistently high.
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