Multiple choice

The contraction and relaxation phases of a muscle constitute

  1. beat

  2. twitch

  3. condition

  4. stimulus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A single muscle twitch consists of a contraction phase followed by a relaxation phase. This is the fundamental unit of muscle activity in response to a single stimulus. 'Beat' refers to cardiac muscle, 'condition' is not a standard term, and 'stimulus' is the trigger, not the response.

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