The diagram shows the secretions of the pancreas in response to three different substances in chyme. each pair of bars represents the response of the pancreas to a different variable. pancreatic juice is composed of bicarbonate in the presence of hydrochloric acid.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

bacterium is not correct