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Set 1: Inferences

Explanation

Answer: A

PASSAGE

Dr. Amelia Chen spent three years studying the sleep patterns of dolphins. Unlike most mammals, dolphins must consciously control their breathing, which means they cannot fall completely asleep. Dr. Chen observed that dolphins let one half of their brain sleep at a time while the other half stays awake, a phenomenon called unihemispheric sleep.

Based on the text, what can most reasonably be inferred about dolphins?

A. They would drown if both halves of their brain slept at the same time.✓ Correct
B. They are more intelligent than other mammals.
C. They never truly rest.
D. They cannot survive in deep water.

Detailed Explanation

The passage states dolphins must 'consciously control their breathing' and cannot fall completely asleep. If both brain halves slept, they would lose conscious control and stop breathing underwater.

Key Evidence:

• "consciously control their breathing"

• "cannot fall completely asleep"

Why others are wrong: B (Intelligence is not discussed in the text.), C (They do rest—just one brain half at a time.), D (Depth is not mentioned; the issue is breathing control.).

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