ABO blood grouping of humans is an example of co-dominance. Homozygotes (IAIA and 1815) express either the A or the B
phenotype. Heterozygotes (1215) express both phenotypes equally and the IAB individual has blood type AB. Blood type O is
the result of the genotype 1°1°: this blood type is considered the recessive trait and is the recessive allele for blood type.
Consider the genetic cross for blood type of these two parents. The father is type A and the mother is type B. Both have the
recessive allele for blood type 0. What is the probability that these parents will have offspring with type A blood?
red flowered plant and white flouvared lant is an ayamole

In ABO blood grouping of humans, when the genotype that determines the type of blood contains the recessive O gene in the parents, a father with a blood type A and a mother with a type B will have a 25% chance of having a offspring with type A blood.

Explanation:

Blood type is determined by the presence or absence of surface antigens A and B.

In the case raised, the parents, type A (A | O) and B (B | O) will have an offspring:

Alleles      A         O

B            A|B        B|O

O           A|A        O|O

This shows that the chances of having a offspring with a blood type A is 25%.

Learn more:

Inheritance - ABO blood group link

that scientist would be robert hooke