The two auricles are demarcated externally from the ventricles by an irregular groove called:

Which valve is located between the left atrium and the left ventricle?

Heartbeat can be initiated by

Purkinje fibers primarily help in the contraction of which part of the heart?

Which of the following organs contains all four types of tissues?

Given below are two statements.
Statement $I$: Visceral layer of serous pericardium forms the outer wall of human heart.
Statement $II$: Epicardium is formed of a thick layer of cardiac muscles.
In the light of the above two statements,choose the correct answer from the options given below.