Question

with age, muscles can become weaker. this is due to __________. a. connections between nerves, which cause more pain and therefore less use b. damage from everyday use and injuries that accumulate over time c. disconnections between motor nerves and muscle fibers d. difficulties that occur during muscle growth and repair please select the best answer from the choices provided. a b c d

Explanation:

• Option A: Nerve connections causing pain and less use is not the primary reason for age - related muscle weakness. Muscle weakness with age is more about structural and functional changes in muscles and their nerve - muscle interactions rather than just pain - induced disuse.
• Option B: While everyday use and injuries can contribute to muscle issues, the main age - related muscle weakness is not mainly due to accumulated damage from use and injuries. There are more intrinsic changes like the disconnection between motor nerves and muscle fibers.
• Option C: As people age, there can be a disconnection (or loss of connection) between motor nerves and muscle fibers. This disrupts the normal signaling for muscle contraction and maintenance, leading to muscle weakness.
• Option D: Age - related muscle weakness is not primarily due to difficulties during muscle growth and repair. The growth and repair mechanisms themselves become less efficient, but the main structural change related to nerves and muscle fibers is a key factor.

Answer:

C. disconnections between motor nerves and muscle fibers