Answer:
The correct answer is B. Myocardium
Explanation:
Our heart is made up of three layers which are epicardium, myocardium, and endocardium. The outer layer is epicardium, the middle layer is myocardium and the innermost layer is endocardium.
The majority of the mass and thickness of the heart is myocardium. Myocardium is muscular layer that is made from cardiac muscle tissue and is responsible for contraction and relaxation which results in pumping of blood and heartbeat. Therefore the correct answer is B.
