My understanding is Multiple Alleles is a form of Codominance with the difference being that Codominance only deals with two alleles whereas Multiple Alleles deals with three or more alleles (such as A, B, AB, O blood). Is this correct?
I would say for simplicity yes, you're right. But in the real world many traits have more than 2 or 3 alleles of different genes affecting a trait, which falls under polygenetic traits or multifactorial traits.
My understanding is Multiple Alleles is a form of Codominance with the difference being that Codominance only deals with two alleles whereas Multiple Alleles deals with three or more alleles (such as A, B, AB, O blood). Is this correct?