Answer:
chordates
Step-by-step explanation:
A cladogram is a diagram used to visualize phylogenetic relationships that living beings have established in an evolutionary way over the years.
As you can see in the question above, a cladogram is basically formed by a main feature (representing the evolutionary lineage) that is divided into parallel features that have some nodes, or more features. These traces show the moment when the evolutionary lineage gave rise to another taxon of biological classification. However, what matters to answer the question above, is that you know that in the species that are closest to each other in relation to the main line of the cladogram are more closely related. So we can say that chordates are the closest group to echinoderms .