Heredity is the passing on of traits, or characteristics, from parents to offspring. Genes are the tiny coded messengers responsible for passing on the traits. Each gene is composed of one of many possible combinations and sequences of DNA, which signals an organism to produce different types of proteins. These proteins control every detail of how an organism will grow and develop. The most complicated creatures as well as the simplest one celled bacteria are all directed by a coded set of instructions written in its DNA. Every gene occupies a certain location on a chromosome strand, and every organism has a unique number and order of genes on its chromosomes. The more closely related two organisms are, the more alike their chromosomes. All organisms that use sexual reproduction have two strands of chromosomes in the nucleus of each cell. Humans, for example, have 23 pairs of chromosomes, for a total of 46, in every cell. Which of the following organisms likely have the most similar chromosomes? A Humans and frogs B Birds and lions C Humans and apes D Lions and alligators