If a heterozygous type B female and a heterozygous type B male have a baby what are the chances the baby will have type O blood

The chances that the baby will have type O is 25%

Explanation: Both the male and female are heterozygous for type B blood, this means that they both have one dominant allele for type B blood and one recessive allele for type O blood. Remember that in the ABO blood system, The alleles for type A and B are dominant while the allele for type O blood is recessive.

This means that the genotypes of both parents for type B blood is BO.

BO x BO = BB, BO, BO, and OO.

Phenotypically, BB and BO will manifest as type B blood while OO will manifest as type O blood.

From the cross between the two parents, one out of the four offsprings has type O blood, therefore the chances of a child having type O blood is 1/4 x 100 = 25%.

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