Final answer:
Alleles are alternative forms of a gene that govern the same feature and are found on matching positions of homologous chromosomes. They contribute to genetic diversity and determine specific traits.
Step-by-step explanation:
The answer to the student's question is: alleles are alternative forms of a gene that govern the same feature, such as eye color, and occupy corresponding positions on homologous chromosomes.
Homologous chromosomes are a pair of chromosomes in a diploid organism that have the same size and shape and contain the same genes in the same locations. Each chromosome of the pair comes from a different parent, allowing for genetic diversity due to the different alleles present.
These alleles can be the same sequence (like AA, BB, or OO) or different (like AB). The combination of alleles determines the trait or phenotype of an organism, such as blood type or eye color. This is essential for understanding how traits are inherited and how they contribute to the variation within a species.