Where is the phot for the video?
This is called a chemical bond.
Answer:
Lungs supply oxygen carried by blood to cells of the body. The cells which are responsible for the transportation of oxygen is hemoglobin. When oxygen rich hemoglobin reaches a cell so the oxygen is unloaded and carbondioxide which is produced as a waste product is loaded in hemoglobin. Again this hemoglobin goes to the lungs and dispose carbondioxide there and repeat the process again.
I think the answer is 1. after
