Which kinds of cells are always single-celled? a). eukaryotes b).prokaryotes

B

Explanation:

prokaryotes

It’s prokaryotes because it’s like bacteria and stuff and eukaryotes are for people, plants and animals

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.