What are the collecting chambers of the heart? What are the pumping chambers of the heart?

What are the collecting chambers of the heart? What are the pumping chambers of the heart? The heart is made up of four chambers. The upper chambers are the called atria and act as the receiving chambers. There are four valves within the heart, which help control the direction of blood flow. Blood low in oxygen returns from the body and enters the right atrium.  The lower chambers are called ventricles; these are the pumping chambers.           I really hope this helps!! Have an amazing day <3

i think it is dna, i'm not totally sure but i think it might be.

sulfur dioxide

explanation: acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air. these substances can rise very high into the atmosphere, where they mix and react with water, oxygen, and other chemicals to form more acidic pollutants, known as acid rain.