Answer:
Index
Explanation:
An index fossil can be used to identify a specific period of time. Organisms that make good index fossils are distinctive, widespread, and lived briefly. Their presence in a rock layer can be used to identify that period of time over a large area.
It's D because it's found in the <span>cell's plasma membranes (at high concertration levels)
Hope this helps!! :-)</span>
They are related because they are all in the same blood or family you breathe in oxygen and remove carbon dioxide the carbon dioxide it helps other stuff in the ecosystem to survive or live so its like this people breathe oxygen while plants breathe carbon dioxide.
The correct answer would be "Density is the amount of matter in a certain volume"
