Endocytosis is used by cells to do which of the following actions? a. secrete large molecules into the extra cellular space
b. ingest it take in bacteria and cell debris
c. movement of molecules out of the cell
d. retrieve elements of the plasma membrane after exocytosis

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.