1. natural selection acts on existing traits because you can not evolve into something you didn't have
2. original structures evolve to accomplish new function in order to survive
Can you show an image of the question?
The answer should be altitude
Ans: Cells are so small because it allows them to have a better surface area to volume ratio. This makes it much easier for the cell to bring in necessary nutreints and excrete wastes. Also the smaller the cell is, the less time it takes to replicate the small cell as opposed to a bigger cell.
Answer:
genrally it includes the population ,community, ecosystem,and biosphere .An ecosystem is all the living things in an area interacting with all of the abiotic parts of environment
