Dr McCallum's Class Is Learning About Genes

Dr. McCallum's class is learning about genes. He explains that not all of the information contained in our genes is used, either because the environment doesn't trigger certain tendencies or because another genetic tendency took precedence. The genetic information that is active in a particular person is expressed through observable characteristics. We call these characteristics

A) genotypes.
B) phenotypes.
C) alleles.
D) chromosomes.