Answer the following question given this paragraph: 

The cardiovascular system consists of the heart, a network of blood vessels, and blood. Blood is a liquid tissue. The heart is a pump that keeps blood flowing through the vessels of the system.


Q: Which system in the human body consists of the heart, a network of blood vessels, and blood?

 Choices:

- cardiac system

- nervous system

- circulatory system

- cardiovascular system

A:
cardiovascular system
