Question

how does circulation of blood take place in humans

Answer 1

It consists of the heart and the blood vessels running through the entire body. The arteries carry blood away from the heart; the veins carry it back to the heart. ... In the systemic circulation, the left ventricle pumps oxygen-rich blood into the main artery (aorta)......

Answer 2

the main organ which circulate the blood is h e a r t .. human heart has 4 chambers left and atrium and left and right ventricle

artery thick walled vessel which carry blood from heart to different parts of the body
veins are thin-walled vessels which carry blood from different parts of the body to the heart