Final answer:
Two or more alternative forms of a gene located at the same position on paired chromosomes are known as alleles. Homologous chromosomes are pairs that contain the same genes, and different alleles lead to variations in traits such as hair color.
Step-by-step explanation:
Two or more alternative forms of a gene that occupy the same position on paired chromosomes are called alleles. These homologous chromosomes are a pair of chromosomes that have the same size and shape and contain the same genes, which are the functional units of chromosomes determining specific characteristics by coding for specific proteins. For instance, different alleles are responsible for the trait variations such as hair color that can be blonde, brown, or black.
A diploid organism, which has two sets of chromosomes, can have either identical alleles (homozygous) or different alleles (heterozygous) for a given trait on their homologous chromosomes. The existence of these alleles is the result of gene variants arising by mutation. When they occur at the same locus on each chromosome of a pair, they present options for a given trait. Research into these variations, which include Mendelian examinations of inheritance, provides essential insights into genetics and how traits are passed down through generations.