What is the probability that both parents will contribute a recessive allele for any given trait? Use the product rule to determine the probability of inheriting the recessive genotype (aa).

The probability of inheriting the recessive trait from both parents is 25%

Explanation:

According to the product rule when two alleles independently assort the probability of them occurring together is calculated by each of the probability.

In this case:

Since each allele is a 1/2 chance of 50% probability to be in inherited from either parent is 1/2*1/2=1/4 or 25%

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.