Which two monomers may combine to form a polyester?

In the mouse, gene a allows pigmentation to be deposited in the individual coat hairs; its allele a prevents such deposition of pigment, resulting in an albino. gene b gives agouti (wild-type fur); its allele b gives black fur. what would the expected ratio of the progeny be in a cross of a doubly heterozygous agouti mouse mated with a doubly homozygous recessive white mouse? 1 (agouti) : 1 (black) : 1 (albino) 9 (agouti) : 3 (black) : 4 (albino) 3 (agouti) : 4 (black) : 9 (albino) 1 (agouti) : 1 (black) : 2 (albino) 9 (black) : 27(albino)