Final answer:
The physiology of an animal is part of its phenotype, which depends on its genotype and environmental influences. The correct pairing is phenotype and genotype (option B). Environmental factors play a pivotal role in expressing these genetic traits.
Step-by-step explanation:
One theme in physiology states that the physiology of an animal is part of its phenotype, which is based on its genotype and environmental influences. The correct answer to this statement is B) phenotype; genotype. The phenotype refers to the observable traits expressed by an organism, such as hair color, skin color, height, and build, and it results from both the organism's genotype—the genetic makeup inherited from its ancestors—and the influence of environmental factors.
Environmental factors can significantly affect phenotypes. For example, sunlight and food availability can influence how genes are expressed. Hence, while genotype provides the genetic code, the phenotype may vary depending on how those genes interact with the environment.