Answer:
The heart is made of 4 chambers.
a) Right auricle/atrium
b) Left auricle/atrium
c) Right ventricle
d) Left Ventricle
Blood enters the right atrium via the Venacavae (2 veins), is squeezed to the right atrium, enters the pulmonary arteries and goes to the lungs for purification.
After purification the lungs send the oxygenated blood back to the heart through the pulmonary veins and enters the left atrium from where it is sent to the aorta and then to all parts of the body through the left ventricle.
So it acts as a double pump as it pumps blood twice through a single cycle through the body.