Q: What muscle is found only in the walls of the heart?


Read this paragraph and choose the correct option from the provided answers:

Cardiac muscle is found only in the walls of the heart. When cardiac muscle contracts, the heart beats and pumps blood. Cardiac muscle contains a great many mitochondria, which produce ATP for energy. This helps the heart resist fatigue. Contractions of cardiac muscle are involuntary like those of smooth muscle.

 Choices:

- respiratory muscle

- abdominal muscle

- skeletal muscle

- cardiac muscle


A:
cardiac muscle