Generated by claude-sonnet-4-6 · 2026-06-15 06:45 · grounding rag
Model Answer
(a)
(i) Autotrophs capture only 1% of the solar energy available to them.
(ii) Only 10% of the energy at one trophic level is transferred to the next level (10% law).
(b)
Trophic levels are the steps in a food chain at which organisms occupy a feeding position, e.g., producers (plants), primary consumers (herbivores), secondary consumers, and tertiary consumers.
Food chains do not exceed 4–5 trophic levels because only 10% of energy passes from one level to the next. By the fourth or fifth level, the available energy becomes so small that it cannot sustain any further organisms. Thus, energy loss limits the length of a food chain.
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Explanation
- Part (a) needs two specific figures: 1% (solar energy fixed) and 10% (energy transfer between levels) — both are standard facts from the "Our Environment" chapter (Ch. 15).
- Part (b): define trophic level briefly, then explain the energy limitation (10% law / loss as heat) as the reason for short food chains. Examiners expect the concept of progressive energy loss, not just the percentage.
- The source passages provided were from other chapters (Chemistry/Physics/Biology – respiration/optics), so this answer is based on the standard NCERT Biology Ch. 15 content as expected for this question type.