Question

Which of the following genotypes is homozygous recessive?
Answer
ss
Bb
TT
XY

Answer 1

With simple questions like these, I find it best to explain the question...rather than give the answer.
To simplify:

Dominance in alleles refers to the occurrence where one allele masks the presence of another. These alleles are usually shown with capital letters, such as the "B" in the above problem.

Recessive in alleles refers to one allele which will be masked unless both alleles are recessive, which will not allow for a masking. These are shown with lower case letters, such as "b" in the problem above.

Heterozygosity refers to situations where one locus is dominant and the other is recessive.
Homozygosity refers to situations where both loci are either dominant or recessive.

Knowing that, what do you think the answer is?

Answer 2

ss

Answer 3

Exactly, very good!

Answer 4

thanks