yes
No. They can have an O positive, an O negative, A B positive, or a B negative child.
If the mother is A negative, and the father is B positive, they could have children who are A negative, A positive, B negative, B positive, AB negative, AB positive, O negative, or O positive.
if your child is negative, i would ask for a blood sample from the mailman
yes
o positive
no
No
If the mother's genotype is AO, then it is possible that the child can be type O-
If mother is heterozygote yes.
if your child is negative, i would ask for a blood sample from the mailman
If the mother's genotype is AO, then it is possible that the child can be type O-
no