Answer:
Hagfish are a type of non-vertebrate chordate--not a true fish, but not a true invertebrate.
Lamprey is a true fish that is a Parasite.
Gills are need to help the fish breath. Gill Filaments. The gill filaments in fish have functions like lungs in people: it's the organ responsible for absorbing oxygen and expelling carbon dioxide
How jawless fish eat
the seafloor into their mouth, releasing water and waste out of their gills.
