Final answer:
The correct answer is D. left ventricle. The left ventricle contracts during the ventricular systole phase of the cardiac cycle to pump oxygen-rich blood through the aortic valve into the aorta and throughout the body.
Step-by-step explanation:
When the left ventricle contracts, blood is forced through the aortic valve, into the aorta, and throughout the body. The left ventricle is the chamber of the heart responsible for pumping oxygenated blood to the systemic circulation. During the cardiac cycle, after the atria fill the ventricles with blood during diastole, the ventricles then begin their contraction, known as ventricular systole. During systole, the left ventricle contracts, creating enough pressure to open the aortic valve and allowing blood to flow into the aorta. The aorta is the main artery that carries oxygen-rich blood from the heart to the rest of the body.
Cardiac muscle is distinctive and operates under a unique system of electrical impulses, starting at the sinoatrial node, with the atria contracting in unison, followed by a pause at the atrioventricular node that allows atria to fully empty their blood into the ventricles. Cardiomyocytes are the muscle cells that make up the heart, contraction occurs rhythmically and involuntarily, with the function of the heart being to pump blood through the coronary, pulmonary, and systemic divisions of the circulatory system.