Which of the following muscles is classified as striated?

Striated muscles are characterized by their unique banded appearance and include both cardiac and skeletal muscle. Cardiac muscle, which makes up the heart, is distinctly striated due to the arrangement of actin and myosin filaments that are organized into sarcomeres. This striation allows for efficient contraction of the heart, enabling it to pump blood effectively throughout the body.

In contrast, smooth muscle, found in the walls of hollow organs (such as the intestines and blood vessels), lacks this striated appearance. It functions involuntarily and is responsible for movements that are not under conscious control. The term "immovable muscle" typically does not refer to a specific muscle type but may describe skeletal muscles that anchor bones, allowing for joint stability without movement. Involuntary muscle refers to muscles that operate without conscious thought, which includes both cardiac and smooth muscle, but it does not specify the striated type. Therefore, the classification of cardiac muscle as striated is accurate, emphasizing its structural and functional uniqueness within muscular tissue.