Final answer:
The absence of Hox genes is the characteristic that distinguishes an animal belonging to the Phylum Ctenophora from the Phylum Cnidaria.
Step-by-step explanation:
The characteristic that would allow you to conclude that the animal belongs to the Phylum Ctenophora rather than the Phylum Cnidaria is the absence of Hox genes in the Ctenophora. Hox genes play a crucial role in the development of body plans in animals. They are responsible for determining the identity and positioning of different segments in the body. Since Cnidaria have Hox genes but Ctenophora lack them, the absence of Hox genes in the examined animal would indicate that it belongs to the Phylum Ctenophora