4. In cats, a gene for coat color is sex-linked. Cats homozygous for allele A have yellow
coats; those homozygous for allele a have black coats; and heterozygous have tortoise
shell coats. what type(s) of offspring would result from a mating of black male and a
tortoise-shell female? Is it possible to obtain a tortoise-shell male? Explain.

Explanation:

You can get 1/4 tortoise female; 1/4 black female; 1/4 yellow male; 1/4 black male.

IT IS NOT possible to obtain a tortoise-shell male primarily because to have tortoise shell one has to be heterozygous. In case of males, they are hemizyogous so they only get one chromosome with the gene because they have XY and we know this disease is linked on X chromosome because different combinations give us different colors.

I say they are hemizygous because For example, most of the genes of the X chromosome and Y chromosome in human males are hemizygous since males have only one X chromosome (and one Y chromosome) (unlike females that has two X chromosomes).  

OK for this is a punnett square. On one side it would be aa and another would be Aa. When you do so there would be Aa, Aa,aa and aa.

Explanation:

1st question: Aa, Aa, aa and aa.

2nd question: To get any gender is 50/50 so you can never know if it is a male or female.

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.