Question

based on the picture, which phylum does the platypus belong in?
animalia
monotremata
chordata
mammalia

Explanation:

The platypus is a vertebrate, and vertebrates belong to the phylum Chordata. The taxonomic hierarchy in the image shows Chordata as a phylum (between Animalia and Mammalia), and the platypus, being a mammal with a notochord (at some stage), falls under Chordata. Animalia is a kingdom, Mammalia is a class, and Monotremata is an order, so Chordata (phylum) is the correct taxonomic level for phylum here.

Answer:

Chordata