Final answer:
The most superficial layer of the heart is the epicardium, which also serves as the inner layer of the pericardium and provides the heart's outer covering.
Step-by-step explanation:
The most superficial layer of the heart is the epicardium. The heart has three layers, each with its own function. The layers from the most superficial to the deepest are the epicardium, the myocardium, and the endocardium. The epicardium serves as the outermost layer of the heart and is also considered the innermost layer of the pericardium, known as the visceral pericardium. Meanwhile, the myocardium is the middle layer consisting of cardiac muscle tissue responsible for the heart's contraction, and the endocardium is the innermost layer that lines the heart chambers and valves with a smooth layer of cells.