Question

In the summer, the arctic fox appears brown

because its cells produce a dark pigment.
However, in the winter, the arctic fox appears
white because the dark pigment is not produced.
The color change is most likely due to the effect of
(1) different genes produced in the different
seasons
(2) increased pollution on genetic mutations
(3) environmental conditions on gene expression
(4) poor nutrition on cell growth and development

Answer 1

The color change is most likely due to the effect of "(3) environmental conditions on gene expression" All these changes have to do with what will keep the fox alive for the longest amount of time.