Q1. [3] deep thorough-understanding
A student argues that since reflex arcs already handle quick responses to danger, the brain's role in the nervous system is redundant. Why is this argument incorrect? Give TWO distinct reasons.
Generated by claude-sonnet-4-6 · 2026-06-26 01:01 · grounding rag
Model Answer
The argument is incorrect for the following reasons:
- Reflex arcs handle only simple, automatic responses (like withdrawing from pain), but the brain is essential for complex thinking, decision-making, and voluntary actions such as writing, talking, or riding a bicycle. These require the fore-brain to receive, interpret, and integrate sensory information before directing motor responses.
- Involuntary functions and coordination of body processes — such as regulating blood pressure, salivation, posture, and balance — are controlled by the mid-brain and hind-brain (including medulla and cerebellum). Reflex arcs cannot perform these functions.
Thus, the brain is far from redundant; it is the main coordinating centre of the body.
Source: Chapter 6, Sections 6.1.1 and 6.1.2
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Explanation
- Examiners expect two clearly distinct reasons — award yourself 1 mark each for the two reasons and 1 mark for the concluding point or overall coherence.
- Avoid mixing the two reasons; keep them separate.
- Key terms to use: fore-brain, voluntary actions, medulla, cerebellum, coordinating centre — these signal textbook knowledge and earn marks.
- Do not just say "brain does more things" — name what it does specifically.