Generated by claude-sonnet-4-6 · 2026-06-11 09:50 · grounding rag
Model Answer
(a) Birds and mammals are warm-blooded animals that maintain a constant high body temperature. This requires a lot of energy, so they need highly efficient oxygen supply. Mixing of oxygenated and deoxygenated blood would reduce the efficiency of oxygen delivery to tissues, making them unable to sustain the high metabolic rate needed.
(b) Amphibians and reptiles can tolerate some mixing of the two blood streams. Their body temperature depends on the temperature of the environment (they are cold-blooded/poikilothermic).
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Explanation
- The key concept for (a) is the link between warm-bloodedness, high energy demand, and the need for pure oxygenated blood.
- For (b), examiners expect the names amphibians and reptiles and the term environmental temperature (or that they are cold-blooded/ectothermic). These points come from Chapter 7 (Control and Coordination / Life Processes context) of the NCERT textbook. Note: the source passages provided are from other chapters, but this is standard NCERT Biology content for Class 10, Chapter 6 (Life Processes).