By studying pea plants, Mendel concluded that traits of all organisms are passed from parents to offspring. This passing of traits onto offspring is called

Fundamental theory of heredity.

d is the answer

sorry if its wrong!

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.