1. All known living things are made up of one or more cells.
2. All living cells arise from pre-existing cells by division.
3. The cell is the fundamental unit of structure and function in all living organisms.
I hope that this helps you !
Answer:b) The air at high altitudes are less dense, so its harder to breathe.
Explanation:
AS altitude increases, the air pressure drops. This reduces the amount of gas molecules in the air so the air becomes less dense compared to air closer to sea level.
That's how the food chain works. There isn't much to it.
Charles Wilson Peale I believe.