Question

multiple choice question
which of the following is not a true statement about the myofilaments responsible for contracting and relaxing musc
a. for body movement to happen, myosin and actin must float away from one another to expand the muscle.

b. actin are relatively thin strands of protein that attach to one end or the other of the sarcomere.

c. myosin are relatively thick strands of protein and are studded with heads resembling knobs.

d. in a sarcomere, strands of myosin float between strands of actin.

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Explanation:

To determine the false statement, we analyze each option:

• Option B: Actin (thin filaments) attach to sarcomere ends—true.
• Option C: Myosin (thick filaments) have knob - like heads—true.
• Option D: In a sarcomere, myosin (thick) is between actin (thin) filaments—true.
• Option A: For muscle contraction (movement), myosin heads attach to actin and pull them closer (shortening the muscle), not “float away” to expand. This is false.

Answer:

A. For body movement to happen, myosin and actin must float away from one another to expand the muscle.