The answer is A. I took the quiz and test. this is what it was for edgunuity. hope this helped.
Answer:
The heart is made of three layers of tissue. Endocardium, the thin inner lining of the heart chambers that also forms the surface of the valves. Myocardium, the thick middle layer of muscle that allows your heart chambers to contract and relax to pump blood to your body.
Explanation:
The answer to this question would be C or B hope this helps
