The number of alleles controlling blood groups in humans? by Sunday | Sep 7 | Biology JAMB | 0 comments A. 3 B. 4 C. 5 D. 2 Correct Answer: Option A – 3 Users Also Read These:A person with blood group B can only donate blood to…When both alleles in a heterozygous individual are…A cross between two parents produced four…A person with blood group, O can be given blood from…If a person has two alleles of the sickle cell…