Tissue layers making up the heart wall include which of the following? 1. Endocardium 2. Epicardium 3. Myocardium

a. 1, 2, and 3
b. 2 and 3 only
c. 2 only
d. 1 and 3 only

ANS: A
The heart wall consists of three layers: (1) the outer epicardium, (2) the middle myocardium, and (3) the inner endocardium.