1. What cause eyes to be different colors?

The color of our eyes comes from the appearance of the pigment that is present in the iris, the central part of the eye. Brown eyes are rich in melanin pigment deposits, making them darker, while blue eyes lackmelanin. Heterochromia happens when the concentration and distribution of melanin isn't uniform.

Explanation:

Eye color is determined by genetics. The eyes can naturally change their color as a response to the iris expanding or contracting in the presence of light or as the iris ages. This results in the eyes gradually becoming darker or lighter in color.

b brown mice / white sand dunes

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.