The muscular system is composed of approximately 600 muscles

The appropriate response is skeletal muscles. Skeletal muscle is one of three noteworthy muscle sorts, the others being heart muscle and smooth muscle. It is a type of striated muscle tissue which is under the "willful" control of the substantial sensory system. Most skeletal muscles are joined to bones by groups of collagen strands known as ligaments.

Musculas system consists of Skeletal, smooth and cardiac muscles.Cardiac muscles are found in the walls and There are 639 Skeletal muscles in Human body. So answer to your question is the muscular system is composed of approximately 600 Skeletal muscles.

They need to contract and relax