How do the ratios with oxygen change down a group?

rocks and weathering-matching

not sure if this what   you'r looking for would be percent composition

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.

colors do exist. the color of the sky is actually violet; humans percieve the color of the sky as blue.