Let's think step by step! What do muscle fibers need to do to enable movement?\nOptions:\n- (A) Bend\n- (B) strength\n- (C) exercise\n- (D) ligt\n- (E) It expands\n- (F) shorten\n- (G) Vibrates\n- (H) stay warm
The thinking starts now:
User
Muscle contraction occurs when muscle fibers get shorter. Movement is based on the contraction of muscles. Movement happens when muscle fibers get shorter. The final answer: (F).
Assistant