Answer:
Recessive alleles are denoted by a lowercase letter (a versus A). Only individuals with an aa genotype will express a recessive trait; therefore, offspring must receive one recessive allele from each parent to exhibit a recessive trait.
Explanation: Is this what you were looking for?
Answer:
because the frog is not really persons that the reasons why frog less the circulatory sysyem
I would go with b-genetic engineering (:
