Consider the mammalian heart. Why is the muscular wall of the left ventricle thicker than that of the right ventricle?

The left ventricle is the one in charge of impulsing the blood to the aorta, and then this moves through the body.

The right ventricle is the one in charge of move the blood to the pulmonary vein, and then to the lung to be oxygenated.

The left ventricle is thicker because the blood that moves to the aorta has to be with more pressure, and this requires more contraction power.

The muscular wall of the left ventricle is thicker than that of the right ventricle because the left ventricle requires higher forces to carry out its function - pumping blood through the systemic circuit.

Explanation:

The ventricles are located at the bottom of the heart. Their main function is to collect and pump blood to the rest of the body.

The right ventricle pumps deoxygenated blood into the lungs via the pulmonary artery. It requires a low pressure to carry this function out.

The left ventricle pumps oxygenated blood to all the tissues in the body. As a result, it requires higher forces than the right ventricle. Therefore, the muscle wall of the left ventricle is thicker than that of the right ventricle (it is the thickest of all the heart chambers).