Abduction requires the action of two muscles, and adduction requires the action of

The correct answer is "four muscles".
Abduction and adduction are terms referring to the movement of the limbs or other body parts. More specifically, abduction refers to the pulling of the body parts away from the midline of the body, while adduction refers to the movement of any body part towards the midline of the body. Movements involving abduction incorporate two muscles, while movements involving adduction require the action of four muscles. 

Where are the following