Final answer:
The animal with 6 gill slits, a tube shaped body, and no lower jaw is a jawless fish, examples of which are lampreys and hagfish.
Step-by-step explanation:
The super-class animal with 6 gill slits, a tube shaped body, no paired fins, and lacking a lower jaw is classified as a jawless fish. These creatures, such as lampreys and hagfish, evolved before jawed vertebrates and represent an ancient lineage. Characteristics of jawless fish include a notochord, paired gill pouches, a pineal eye, a cartilaginous skeleton, and a two-chambered heart. Lampreys are known for their toothed, funnel-like sucking mouth which they use to feed parasitically on other fish.