Amuscle that swings two long bones in an arc toward each other is a

A muscle that swings two long bones in an arc toward each other is a flexor and an example of hamstring muscle.

Explanation:

The hamstring muscle is a complete muscle that encompasses 4 counterparts they are the short head of the biceps femoris, the long head of the biceps femoris, the semi membranosus, and the semitendinosus.

They are located at the knee and the hip joint and plays a major role in supporting physical activities such as walking , running , jumping and  rotation of the knees.

i am going to guess that it is co2.