Question

multiple choice question
the heart and blood vessels are components of the ______ system.
respiratory
cardiovascular
lymphatic
digestive

Explanation:

The heart and blood vessels are the main parts of the system that circulates blood throughout the body, which is known as the cardiovascular system. The respiratory system deals with gas - exchange, the lymphatic system is related to immune function and fluid balance, and the digestive system is for breaking down food.

Answer:

B. cardiovascular