There are two types of alleles. An allele that masks another is the homozygousX phenotypealleleX recessiveheterozygous✔ dominantgenotype allele. The one that is masked is called the homozygousphenotypeallele✔ recessiveX heterozygousX dominantgenotype allele.An organism that has the same alleles for a particular trait is ✔ homozygousX phenotypeallelerecessiveheterozygousdominantX genotype. An organism that has different alleles for a particular trait is X homozygousphenotypeallelerecessive✔ heterozygousdominantgenotype.