Final answer:
When the left ventricle contracts, it decreases the distance between the base and apex, allowing the ventricle to eject blood at high pressure into the aorta and through the body.
Step-by-step explanation:
When the left ventricle contracts, the distance between the base and apex decreases, identified as the correct event occurring during this phase of the cardiac cycle. This is a component of the ventricular contraction or systole. Detailed explanation: During the ventricular ejection phase, the muscles of the left ventricle contract and create a high pressure within, exceeding the pressure in the aorta. This causes the aortic semilunar valve to open, allowing blood to be pumped through the body.
The blood's ejection from the heart occurs efficiently and at high pressures, in contrast to the right ventricle which operates at lower pressures due to the pulmonary circuit's lower pressure. It's essential to note that the volume of the right ventricle is not increased, the diameter of the ventricular chamber actually decreases, and the efficiency is not minimal, as it develops relatively high pressures.