Question

A scientist has discovered a new gene in oysters. Oysters with the dominant allele for disease resistance 'R' have been found to tolerate polluted waters better than oysters with the recessive 'r' allele. What term is used to describe an oyster that has two identical dominant alleles (RR) for this gene?

A) genetic hybrid
B) homozygous dominant
C) heterozygous dominant
D) heterozyous recessive

Answer 1

The right answer is B) homozygous dominant

We speak of homo / heterozygosity about a locus, that can be represented by several alleles (version). The alleles are dominant or recessive between them.

*So homozygote: same alleles

*heterozygote: different alleles

Consider a locus and 2 alleles:

allele R: dominant

allele r: recessively

*heterozygote: R / r

*homozygous recessive: r / r

*homozygous dominant: R / R

Answer 2

the answer is B I believe