Which of these is an environmental factor that causes
damage to chromosomes?

A. ultraviolet light
B. acid rain
C. methane gas
D. lead paint

A: Ultraviolet Light

Explanation: Chromosome fragmentation can result from UV irradiation occurring at any instance. You can find maximum and minimum amounts of damage when a constant dose is applied at various times.

This is the most closely resembles the model. 

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.