About two thirds of the world's human population survive primarily by eating one or more of three grain crops. what are these three grains? a. corn, wheat, and oats

energy and particles

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.