Final answer:
Option b), The valves between the atria and ventricles are called atrioventricular valves, whereas the valves at the exits of the heart are known as semilunar valves, making b) Atrioventricular; semilunar the correct answer.
Step-by-step explanation:
The valves between the atria and ventricles are called atrioventricular valves, while the valves that guard exits from the heart are called semilunar valves. Therefore, the correct answer is b) Atrioventricular; semilunar.
The atrioventricular (AV) valves consist of the tricuspid valve on the right side of the heart and the mitral or bicuspid valve on the left side. These valves function to prevent backflow of blood from the ventricles to the atria.
On the other hand, the semilunar valves are comprised of the pulmonary valve leading to the lungs and the aortic valve leading to the aorta, which prevent blood from flowing back into the ventricles from the arteries.