Which factor is used to determine whether two organisms are members of
the same species?

According to the biological species concept, organisms belong to the same species if they can interbreed to produce viable, fertile offspring. Species are separated from one another by prezygotic and postzygotic barriers, which prevent mating or the production of viable, fertile offspring.

The correct answer is- It is type O because i is recessive.

There are three different alleles for the ABO gene that are present in the population and responsible for different blood types (A, B, AB, O).

Allele IA, IB, and i corresponds to blood type A, B, and O respectively.

i is a recessive allele and allele A and B are dominant.

Blood group O has genotype ii and it does not contain any antigen on the surface of RBC.