The basic unit of life is known as
the cell.
the nucleus.
the neutron.
the atom.

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.

d. organisms have cells with different shapes and functions.