Consider the generalized cladogram of fish. A cladogram is shown. Part A has bones and jaws.

Osteichthyes is a group of fish that have the derived characteristics of jaws and true bones. Which letter corresponds to where Osteichthyes belongs on the cladogram?
A
B
C
D

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.

d we did this already

yes, because even though a theory has a  lot of evidence to support it, it is not always true