Chordates share some common traits. At some point in their life cycle, they have a notochord, a nerve cord, and pharyngeal (fayr uhn JEE uhl) slits in the neck or throat. The notochord is a flexible rod that supports the animal's back. ... Sharks are one type of vertebrate animal that have backbones made of cartilage.
Genes they assort independently if they follow the 9: 3: 3: 1 rule resulting from a dihybrid cross. It shows that the genes are not on the same chromosome and they are not included.
