Which of the following best explains how a dog is able to ingest and digest food, and remove waste products from its body? Choose 1

A. A dog has systems of specialized cells, such as those that make up the urinary tract and digestive system, that help it carry out these functions.

B. A dog carries out digestion and excretion through a series of redundant systems, so if one system is injured, another will take its place.

C. A dog has cells whose genetic makeup can change depending on the circumstances, such as whether the animal is ingesting and digesting food, or excreting waste.