Awoman and a man are both heterozygous for a recessive allele for a rare genetic disease. if they have one child, what is the probability that he or she will be affected? if they have two children, what is the probability that at least one of them will be affected?

Explanation:

A cross between two heterozygous Aa individuals will produce the followinf offspring: 1/4 AA, 2/4 Aa and 1/4 aa.

Since the disease is recessive, 1/4 of the offspring will have the aa genotype and 3/4 of the offspring will be unaffected.

Every time they have children new gametes were generated independently.

The probability of having no affected children both times is, according to rules of probability for independent events, 3/4 × 3/4 = 9/16 (it's the probability of having a healthy child the first time multiplied by the probability of having a healthy child the second time).

The probability of having at least one affected child is 1 - probability of no affected children = 1 - 9/16 = 7/16.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

the cell cycle is the final answer! : )