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

Explanation:

Motor nerves are located in the central nervous system, their function is to send signals from the central system to muscles, which are formed by fibers. (see image attached).

Therefore, if there's no connections between motor nerves and muscle fibers, there won't be any movement, because nerve signals send the information needed to cause movements. So, if the muscle don't move, it will become weaker, decreasing its strength and size.

need more in formation