Final answer:
Biological materials such as genes, chromosomes, and DNA regulate the development of traits in organisms.
Step-by-step explanation:
Traits in organisms are regulated by biological materials such as genes, chromosomes, and DNA.
Genes, located on chromosomes, control or partially control visible characteristics known as traits, like eye color and hair color. These genes can have multiple variations called alleles, which determine the specific expression of a trait.
Additionally, the interaction between an individual's genes and their environment, as well as epigenetic factors, can also influence the development of traits.