Here's why:

* Genes: Genes are segments of DNA that code for specific traits.

* Alleles: Alleles are alternative forms of a gene. For example, the gene for eye color might have an allele for brown eyes and an allele for blue eyes.

* Pairs: We inherit one allele from each parent, creating a pair of alleles for each gene.

So, when we talk about one specific gene within a pair, we're referring to one of its alleles.