What Blood Type Would a Person Who is Homozygous Recessive

Question

What blood type would a person who is homozygous recessive for all blood type alleles have?
A) A
B) B
C) AB
D) O

Accepted Answer

A person who is homozygous recessive for all blood type alleles (i.e. aa bb cc dd) can only produce the O blood type. This is because the O allele is recessive to both the A and B alleles, and the AB blood type requires both A and B alleles.