Zoologists have attached miniaturized cameras called "critter cams" directly to many species allowing observations in a wide range of natural environments with the use of these tiny cameras minimizing the a. single-blind effect.
b. observer effect.
c. double-blind effect.
d. effects of extraneous correlations.

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. 

While transcription can repeat and make multiple mrna copies of genes, and multiple ribosomes can translate the same mrna