Final answer:
Mary raising the weight over her head from behind is an action of extension, since she is increasing the angle between her arm and torso.
Step-by-step explanation:
Mary raising the weight over her head from behind would be an extension. Extension is the movement that increases the angle between body parts. When Mary lifts the weight over her head, she extends her arm at the elbow and shoulder joints. This is not to be confused with flexion, which would be the act of decreasing the angle, as in bringing the weight down from an overhead position.
Circumduction is a combination of flexion, extension, abduction, and adduction to create a circular motion, but this does not describe simply lifting a weight overhead. Rotation involves a twisting motion around an axis, and adduction is the movement of a body part toward the body's midline, which is also not what is described in Mary's action.