When a trai has more than two alleles how is that trait inherited?

Question

When a trai has more than two alleles how is that trait inherited?

Answer 1

Do you mean when there's only one gene but more than one type of allele as in blood type?  There's no way to predict that.  As an example using human blood type, both A and B are dominant while O is recessive. So if the alleles were A and B (AB blood type) this would be codominance, but AO or BO would produce Type A and Type B respectively, and this would be complete dominance.

If what you mean is a trait like hair or eye color where there are more than one set of genes which control the trait, the word you want is pleiotropy.