Carbon dioxide is formed when two oxygen atoms chemically combine with a carbon atom which term best describes carbon dioxide? A Mixture
B atoms
C elements
D compound

It's a compound

Explanation:

A compound is two or more elements joined together. The fact that two oxygen particles and a carbon particle is joined together means it's a compound.

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.