Which of the following explains why a tree is often used as a model to represent the principle of common descent

When the relationships between species are mapped out, branches spread out from a common trunk, resembling a tree.

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.