A gene map of the human genome
Answer:
The most important are the lungs, more precisely the alveoli.
Explanation:
Alveoli are structures of the lungs where gas exchange occurs. They allow oxygen from the air to pass into blood. Oxygen diffuses through the walls of alveoli into the capillaries that surround it. Oxygen is then bonded with the iron in red blood cells and travels to the heart. The heart then sends the oxygenated blood out to all the cells in the body.
Food is the most important source of chemical energy for living things. The chemical energy in food is converted, or changed, by the body into moving mechanical energy and heat energy. People have invented ways to use the chemical energy of substances to power machines.
