What other word from this unit has the prefix homo - and means to have two copies of the same allele

The correct answer is homozygous.

Homozygous is a term for genotype that has identical alleles for a single trait.

An allele is a form of a gene and diploid organisms have two alleles for a given trait: one inherited from father and one for mother.

Homozygous alleles may be dominant or recessive. A homozygous dominant has two dominant alleles and expresses the dominant phenotype (expressed physical trait), while homozygous recessive has two recessive alleles and expresses the recessive phenotype.