What structures carry inherited characteristics?

Genes are the fundamental units of heredity and are responsible for carrying inherited characteristics from one generation to the next. They are segments of DNA that encode the information necessary for the development of an organism's traits, including physical attributes, behavioral tendencies, and even predispositions to certain diseases. Each gene can exist in different forms, known as alleles, which contribute to variations in specific traits among individuals.

While chromosomes, which are structures within cells, house multiple genes, and alleles represent the specific variations of these genes, it is the genes themselves that directly carry the instructions for inherited characteristics. Therefore, when discussing what specifically carries these inherited traits, genes are identified as the correct answer. This highlights their essential role in the transmission of genetic information from parents to offspring.