Answer:
a. systemic circulation
Step-by-step explanation:
Systemic circulation, also called large circulation, is responsible for ensuring that oxygenated blood is carried throughout the body and that carbon-rich blood returns to the heart. Oxygenated blood leaves the left ventricle through the aorta, is carried to various parts of the body, undergoes gas exchange in the tissues and returns to the right atrium of the heart through the superior and inferior vena cavae. Upon reaching the heart, the carbon-rich blood is then taken to the lung for oxygenation, and the pulmonary circulation process begins again.