Multiple choice An allele can be described as a homozygous genotype a heterozygous genotype a substitute for a gene one of several possible forms of a gene Reveal answer Fill a bubble to check yourself D Correct answer Explanation An allele is an alternate form of a gene. If an individual is homozygous (YY or GG) for a trait, it has inherited the same allele from both parents. If it is heterozygous (YG), it has inherited different alleles for the trait.