Question

5
select the correct answer.
why does your heart never tire of constantly beating to pump blood throughout your body?
o a. it belongs to the skeletal muscle group, which means it moves involuntarily.
o b. it consists of fibers that move voluntarily, so you can train these fibers to increase their endurance level.
o c. it has a high level of muscular strength due to extensive weight training.
o d. it consists of cardiac muscle tissues, which means it moves involuntarily.

Explanation:

Cardiac muscle is involuntary. Skeletal muscle (A) is voluntary. Heart muscle movement isn't voluntary (B). Heart's function isn't due to weight training (C). Cardiac muscle (D) is correct as it's involuntary and makes heart beat without tiring.

Answer:

D. It consists of cardiac muscle tissues, which means it moves involuntarily.