Final answer:
When a homozygous recessive type O individual is crossed with a heterozygous type A individual, 50% of the offspring will exhibit the type A blood. This calculation is based on the basic principles of Mendelian genetics.
Step-by-step explanation:
The student's question asks about the inheritance of ABO blood types, a classic example of Mendelian genetics with multiple alleles.
An individual with homozygous recessive type O blood has the genotype ii. An individual who is heterozygous for type A blood will have the genotype IAi. In this specific cross, the possible genotypes of the offspring will be IAi and ii.
The offspring with the IAi genotype will display type A blood because the A allele is dominant over the O allele. Considering the heterozygous parent can only pass on an IA or an i allele, and the homozygous recessive parent can only pass on an i allele, the offspring have a 50% chance of being IAi and thus expressing type A blood type. So, 50% of their offspring will have type A blood.