Yeast cells of mating type a are genetically engineered to produce only mating factor α instead of the normal mating factor a. The gene for the mating factor receptor was unaltered. How will these engineered cells behave in terms of mating?

Yeast cells

Explanation:

These engineered cells will mate with each other or with normal mating type a cells, but not with normal mating type α  

The sexual cell types of yeast are designated a and α, which are correspondingly conferred by the MATa and MATα alleles of the mating type locus (MAT)

Cells of opposite type can mate to establish a cell of the MATα/MATa diploid state because both MAT alleles are co-dominant, such diploid cells are sterile but can undergo meiosis and sporulation to form asci, each of which contains two MATa and two MATα haploid spores

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait.