Final answer:
Blood type demonstrates codominance and multiple alleles with the IA, IB, and iO alleles being responsible for ABO blood groups, while height is a polygenic trait not explained by simple Mendelian genetics.
Step-by-step explanation:
Blood type is an example of codominance and multiple alleles. In the case of ABO blood groups, the IA and IB alleles are codominant since the phenotype reflects both A and B antigens when both alleles are present (AB blood type). Moreover, unlike Mendel's single gene with two alleles, blood types are determined by three alleles (IA, IB, and iO), making it an example of a gene with multiple alleles where iO is recessive to both IA and IB. Height is less straightforward; it cannot be explained by simple Mendelian inheritance as it is a polygenic trait, influenced by several genes and environmental factors, and does not show a clear dominance or codominance pattern.