Question

what is double circulation?

Answer 1

Let's start with the left side of the heart. Blood enters the left atrium, moves through the bicuspid, or mitral, valve, and into the left ventricle. Blood is then pushed through the aortic semilunar valve into the aorta. This blood is oxygenated and is distributed around the body, providing oxygen to our muscles and organs. Once this blood is deoxygenated, it returns to the heart through a few different veins.

double circulation The type of circulatory system that occurs in mammals, in which the blood passes through the heart twice before completing a full circuit of the body (see illustration). Blood is pumped from the heart to the lungs and returns to the heart before being distributed to the other organs and tissues of the body. The heart is divided into two separate compartments to prevent oxygenated blood returning from the lungs from mixing with deoxygenated blood from the other parts of the body. 

Answer 2

Answer:

The circulation in which the blood passes twice through the heart is called double circulation...

Hope It helps :)