Questions: A muscle that opposes, or reverses, a particular movement is a (n) antagonist synergist fixator agonist (prime mover)

The answer is the first one: antagonist.

Explanation for each option:

1. Antagonist: This is the correct answer. An antagonist muscle opposes or reverses a particular movement. It acts in opposition to the agonist (prime mover) muscle, providing balance and control to the movement.

2. Synergist: This is incorrect. A synergist muscle assists the agonist in performing a movement. It helps to add extra force or reduce unnecessary movement.

3. Fixator: This is incorrect. A fixator muscle stabilizes the origin of the agonist so that it can act more efficiently. It helps to hold a part of the body steady while another part moves.

4. Agonist (prime mover): This is incorrect. The agonist, or prime mover, is the muscle that is primarily responsible for executing a particular movement.

In summary, the muscle that opposes or reverses a particular movement is called an antagonist.