A woman with B-blood has a baby with AB + blood. What are the two possible blood

Someone with blood type AB must have both the A and B alleles. The genotype must be AB. Someone with blood type O has neither the A nor the B allele. The genotype must be OO.

The closure property with regards to polynomials states that polynomials are always closed under multiplication. The coefficients and the exponents can change unlike in addition and subtraction. The variables and coefficients also automatically fit in a polynomial.

Example
A*1 = A
if A = 3, then 3*1=3

this is an example of multiplication under polynomials.