Sally has blood type O and Sam has blood type AB. What are the expected phenotypes when they have kids

Sally has O, so she can only have ii. Sam is AB, so he has to be iAiB. Their kids can be any combination of iA/iB and i/i. So iAi, or iBi. So either type A or type B.

A and B alleles are codominantant to a recessive O allele. Sally WILL give an O allele if she has the O phenotype. Sam will either give an A or a B. the kids will be A or B. not AB or O.

it is impossible to tell if the kids will be + or - as that is a separate protein called the Rhesus protein (discovered in the Rhesus monkey)

Use a punnett square...

across the top, put OO ( o blood is recessive - so it has to be OO)
down the side, put AB, the only genotype of AB blood.
cross in the squares and you will get AO or BO for your children.

Good Luck! :-)

A+
OR
O+