Question

8 after months without practice or physical activity, the unused muscles began to ______, weakening significantly. a uniformity b insidious c atrophy d defiant

Explanation:

We need a verb that describes what unused muscles do when they weaken significantly.

• "uniformity" is a noun meaning consistency, which does not fit grammatically or contextually.
• "insidious" is an adjective describing something harmful that develops gradually, which cannot follow "began to".
• "atrophy" is a verb meaning to waste away from lack of use, which matches the context of unused muscles weakening.
• "defiant" is an adjective meaning showing resistance, which is irrelevant to muscle weakening.

Answer:

C. atrophy