5
QuizMultiple Choice

Unit Test — Unit test

Question 5 • Biology Sem 2 2025-2026

Which statement best describes the step in muscle contraction when the sarcomere is the shortest?

Answer
A
The sarcomere is contracted, and the actin and myosin filaments are partially overlapped.
B
The sarcomere is relaxed, and the actin and myosin filaments are partially overlapped.
C
The sarcomere is contracted, and the actin and myosin filaments are completely overlapped.
D
The sarcomere is relaxed, and the actin and myosin filaments are completely overlapped.

Explanation

A sarcomere becomes shorter as it contracts: the actin filaments slide inward past the myosin filaments, increasing their overlap. At the shortest point, the filaments are described as completely overlapped, so the best choice is “The sarcomere is contracted, and the actin and myosin filaments are completely overlapped.”

AI-written and checked against the verified answer.

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