A muscle group that works with and assists the action of a prime mover is termed a(n) ________. antagonist fixator synergist protagonist a stabilizer

The correct answer is synergist.

In the context of muscle actions, the primary muscle responsible for a specific movement is referred to as the prime mover. However, additional muscles also contribute to this movement in various ways. Muscles that assist the prime mover in performing a movement are termed synergists. They enhance the overall movement effectiveness and can help stabilize joints during the action.

For example, in a bicep curl, the biceps brachii is the prime mover, while other muscles like the brachialis act as synergists to assist in flexing the elbow. In contrast, antagonists are muscles that oppose the action of the prime mover. Fixators and stabilizers serve to maintain posture or stabilize the origin of the prime mover throughout the action. Therefore, the appropriate term to describe a muscle group that works alongside the primary muscle is synergist.