Mom and dad are both heterozygous for the harmful or deleterious recessive trait. what is the probability of their offspring having the illness? % what is the probability of their offspring being a "carrier"? %

25...50.

Let’s assign the dominant allele letter T and the recessive allele letter t. Next step we draw the punnet square below and determine the possible genotype of the offsprings with regards to this trait. It is therefore evident that the probability that the offspring will have the illness (genotype tt) is 25%

50% will be carriers (genotype Tt) like their parents

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