Final answer:
The left ventricle is more muscular than the right ventricle in order to generate a greater amount of pressure to overcome resistance in the systemic circuit.
Step-by-step explanation:
The left ventricle is more muscular than the right ventricle because it needs to generate a greater amount of pressure to overcome the high resistance in the systemic circuit.
Conversely, the right ventricle pumps blood into the shorter pulmonary circuit, which provides less resistance, so it does not need to generate as much pressure.
Figure 19.8 illustrates the differences in muscular thickness between the left and right ventricles.