A synergist is

A) a muscle working in opposition to another muscle.
B) the end of the muscle where the action occurs.
C) the muscle that does most of the movement.
D) the stationary end of the muscle.
E) a group of muscles that work together to cause movement.

A synergist in the context of muscle function is a muscle that assists the primary mover in performing its action. It may help by adding extra force to the movement or by reducing undesirable or unnecessary movement. This definition aligns with the concept of a group of muscles working together to cause movement.