In order for a human female to express a recessive sex-linked trait, she must
a) two recessive alleles
b) an inactive allele
c) a recessive allele on a y chromosome
d) two recessive autosomal alleles

In order for a human female to express the recessive sex linked trait, she must have A. 2 recessive alleles each on her X chromosomes. Assuming complete dominance of alleles on sex chromosomes is followed, and observed, this is tue only particular way that females can phenotypically showcase the trait, as a presence of a dominant allele on any one of her X chromosomes would mask the gene product produced based on the recessive allele, and thus can't be observed phenotypically.

The solution is A.

False. records show otherwise

The answer is joseph is observing the colour of the reaction mixture to see whether proteins are present in the given solution.