If two parents have the blood types AO and BO, what is the chance a child of theirs will have O type blood?
a) no chance, their children will be AO or BO since O is recessive
b) a one in four chance. there is a chance that both pass on their O gene
c)no chance. all of their children will be AB blood type
d) a 2 out of 4 chance. since there are one A, one B, and two O genes