Can someone plz help

What is the broadest level of classification of life

Acladogram is a branching diagram that represents suggested evolutionary relationships among organisms based on the presence of unique traits. a scientist discovers a new organism that lacks limbs and does not have a true backbone. the organism lays eggs to produce offspring and has a cartilage-like rod known as a notochord running along its dorsal surface. on the cladogram below, select the species to which the newly discovered organism is most closely related.

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry