which后面的句子什么成分,修饰哪个的

题目

which后面的句子什么成分,修饰哪个的
In fact a basic amount of movement occurs during sleep which is specifically concerned with preventing muscle inactivity.

答案

which引导定语从句,修饰movement 事实上,睡眠时产生大量活动,该活动与防止肌肉活动停止有关.