Question

this passage describes the xeroderma pigmentosum trait in humans:
xeroderma pigmentosum is a condition that causes skin to be easily damaged by sunlight. humans with xeroderma pigmentosum avoid exposure to sunlight by wearing protective clothing, using sunscreen, and not going outside during the day.
in a group of humans, some individuals have xeroderma pigmentosum and others do not. in this group, the gene for the xeroderma pigmentosum trait has two alleles. the allele for not having xeroderma pigmentosum (e) is dominant over the allele for having xeroderma pigmentosum (e).
justin, a human from this group, has xeroderma pigmentosum.
based on justins phenotype for the xeroderma pigmentosum trait, which of the following could be justins genotype for the xeroderma pigmentosum gene? select all that apply.
ee
ee
ee

Explanation:

Since the allele for not having xeroderma pigmentosum ($E$) is dominant over the allele for having xeroderma pigmentosum ($e$), a person with xeroderma pigmentosum must have two recessive alleles. This is because the dominant allele ($E$) would mask the recessive allele ($e$) if present.

Answer:

ee