What molecule will most likely diffuse through a cell membrane?

Cells destroy body cells infected by a virus or bacteria.

How energy flows through each level in this energy pyramid. is all the matter and energy from one level transferred to the next level?

Which of the following statements is true about the relationship between genetic variation and natural selection? a. genetic variation must be present in a population before natural selection can act on it. b. genetic variation arises in a population as a result of natural selection. c. natural selection can act on a population whether there is genetic variation within the population or not. d. after natural selection acts on a population, the amount of genetic variation in the population always increases.