How do genetics AND the environment affect our traits?

In some situations, genes play a larger role in determining your behavior; in other situations, environment plays a larger role in influencing your behavior. If you had a whole different set of experiences over your lifetime your genes may be expressed in different ways, and you may behave differently than you do now.

Explanation:

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.

it is called the mitotic spindle