Petromyzon attaches itself to the host body with the help of:

Statement $- I :-$ All living members of class $Cyclostomata$ are ectoparasites on some fishes.
Statement $- II :-$ $Cyclostomata$ have a sucking and circular mouth without jaws.

The lamprey $(Petromyzon)$ is included in the same taxonomic class as the

What type of scales are present in $Cyclostomata$?

In which class of animals do the larvae return to the sea after metamorphosis?

Which of the following animals is a true fish?