Which of the following muscles would be classified as voluntary muscles?

Skeletal muscles are classified as voluntary muscles because they are under conscious control. This means that an individual can decide when to contract these muscles, allowing for deliberate movements such as walking, lifting, or speaking. The ability to consciously control skeletal muscles is facilitated by the somatic nervous system, which innervates these muscles.

In contrast, cardiac muscles, which make up the heart, and visceral muscles, found in internal organs, operate involuntarily. Cardiac muscle contractions occur automatically and are regulated by the body's autonomic nervous system without conscious thought. Similarly, visceral muscles also function involuntarily to facilitate processes such as digestion and blood flow.

Antagonist muscles are not a separate category but rather describe pairs of muscles that work against each other to produce movements, such as the biceps and triceps. While some antagonist muscles may be skeletal and therefore voluntary, the term itself doesn't define a type of muscle classification but rather a functional relationship between muscles working in opposition.