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 cannot survive in deep water.

D. They never truly rest.

Detailed Explanation

This question asks you to draw a logical conclusion from the text. 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. A valid inference must be supported by evidence in the passage, even if not stated directly. Look for clues in the text that strongly suggest the answer. Avoid conclusions that require assumptions beyond what's written. Valid inferences are strongly supported by multiple pieces of evidence in the text. Be cautious of choices that go too far beyond what the passage actually states. The best inference is the one most directly supported by textual evidence.

Key Evidence:

• "consciously control their breathing"

• "cannot fall completely asleep"

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