The five main characteristics are foot region, hard exoskeleton, bilateral symmetry, left and right limbs and a segmented body.
Cartilage, bone and fat (see connective tissues section of article)
The answer is B, multiple alleles.
Codominant is when the gene pair in a heterozygous are both fully expressed.
Incomplete dominance is when one allele is not fully expressed over its paired allele.
