D, a net transfer of energy
Answer: they are not living things
Explanation: The virus needs a living cell to multiply because on they're own they can't do anything.
Answer:
Spinach and lettuce, broccoli and cauliflower
Density is mass of object per unit volume
Answer:
4
Explanation:
This is the answer because I have tested it and got it correct. As oxygen-rich (and carbon dioxide-poor) blood travels by a cell the oxygen diffuses through the cell membrane to the area of lower concentration inside the cell. It can do this easily because the oxygen molecule (O2) is very small and has no charge or polarity. The oxygen is used up rapidly by mitochondria.
