Each of us has an ABO blood type, which describes whether two characteristics, called A and B, are present. Every one of us has two blood type alleles (gene forms): one inherited from our mother and one from our father. Each of these alleles can be A, B, orO. Which two we inherit determines our blood type. Here is a table that shows what our blood type is for each combination of twoalleles:

Alleles inherited	Blood type
A and A	A
A and B	AB
A and O	A
B and B	B
B and O	B
O and O	O

We inherit each of a parent's two alleles with probability 0.5. We inherit independently from our mother andfather.

Andreona and Caleb both have alleles A andO.

What blood types can their childrenhave?