Answer:
c. Cardiac muscle contains bands like skeletal muscle, but its contractions are involuntary like smooth muscle.
Explanation:
In Human anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Cardiac muscle is also referred to as myocardium and it's one of the three (3) muscles found only in the heart of vertebrates, the other two (2) being smooth muscle tissue and skeletal muscle tissue.
Cardiac muscle contains bands like skeletal muscle referred to as sarcomeres (contractile units), but its contractions are involuntary like smooth muscle and it's typically being regulated by the sinoatrial node of the heart.
Answer:
I would say We don't have enough evidence or Cell theory is still changing.
Explanation:
There are so many cells in everything so it's almost impossible to know exactly what is going on. Theories about cells have been going on for over 500 years, and we still don't know exactly what is what.
