During a coffee break, your friend spills coffee on your lab coat and the fabric is discovered. is this a true biological stain or simply a compound capable of imparting color?

Coffee stains can be removed from fabric using a combination of warm water, dishwashing detergent, and vinegar. So it's simply a compound capable of imparting color.

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. 

Yes yes yes very good