Bacteria break down organic matter and return carbon dioxide and water to the environment. This is an example. A. combustion. B. Transpiration c. Nitrogen fixation. d. decomposition.​

19. scientists use meteorites that hit earth to provide evidence of the composition of earth's interior because they hypothesize that

Which of these statements are true about scientific theories and hypothesis

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.