Compared to dry environments, evaporation of sweat is in humid environments, resulting in body cooling.

less; reduced

Explanation:

Compared to dry environments, evaporation of sweat is less in humid environments, resulting in reduced body cooling.

In dry environment, the body sweats more in order to compensate for the rate at which evaporation occurs from the surface of the skin. However, in humid environment, sweating is reduced because the rate of evaporation of water from the surface of the skin is not as much as in dry environment. Since evaporation causes cooling, it means that there would be reduced body cooling in humid environments.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.

this is true, assuming that the allele is completely recessive and incomplete dominance is not a factor.