Define the term 'allele'.

The term 'allele' refers to a variant form of a gene. Genes occupy specific positions on chromosomes and are responsible for inherited traits. Alleles are different versions of these genes that can produce variations in characteristics among individuals. For instance, a gene that determines flower color in a plant may have a purple allele and a white allele, leading to different flower colors in the offspring, depending on which alleles are present.

Understanding alleles is fundamental in genetics, as they explain the genetic diversity observed within populations. Each individual inherits two alleles for each gene, one from each parent, and the combination of these alleles can result in different phenotypes. This concept helps to clarify how traits are passed on and expressed in organisms.