Generated by claude-sonnet-4-6 · 2026-06-10 02:56 · grounding rag
Model Answer
Grass contains cellulose, which is difficult to digest. Herbivores need a longer small intestine to allow sufficient time for the complete digestion and absorption of this tough plant material. Carnivores eat meat, which is easier to digest and requires less time, so a shorter intestine is adequate.
Source: Chapter 5, Section 5.2.2 – Heterotrophic Nutrition
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Explanation
- The key concept is cellulose digestion — grass/plant cell walls are made of cellulose, which is hard to break down and needs more time/surface area.
- The passage from Chapter 5 mentions that a cow and a lion differ in their "nutritive apparatus" because food sources differ (stationary grass vs. mobile prey).
- Examiners expect two points: (1) grass is harder to digest, (2) longer intestine = more time/surface for digestion and absorption.
- Do not write about enzymes in detail — that's beyond what the passage states and wastes words.