A Level Biology Practice Exam

The correct answer is arteries, which are the blood vessels responsible for carrying blood away from the heart. They are equipped with thick, muscular walls that accommodate the high pressure of blood pumped from the heart. This structure allows arteries to efficiently transport oxygen-rich blood throughout the body, except for the pulmonary arteries, which carry oxygen-poor blood to the lungs for oxygenation.

In contrast, veins transport blood back to the heart, capillaries are tiny vessels where the exchange of gases, nutrients, and waste occurs between blood and tissues, and venules are small vessels that collect blood from capillaries and connect to veins. These differences highlight the specific functions of each type of blood vessel in the circulatory system.