Looking under a microscope, you note that the cell is a prokaryote. how do you know? it lacks the cell membrane
it lacks nucleus
it lacks genetic material
it lacks cytoplasm

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.

Each member of a class sampled a piece of ptc testing paper. thirty people sampled the chemical. twenty persons were tasters. how many had heterozygous genes? 10 20 0-20 indeterminate

Approximately how many times does an average human heart beat in a lifetime?