The following are the key characteristics of an animal group.
`**` Circular and sucking mouth without Jaws.
`**` Fish like body without scales and paired fins.
a) Name the class in which this animal belongs.
b) Givetwo examples from this class.

From the following general characters find out corresponding Class with an Example a) Exclusively marine, triploblastic, spines on the skin, radially symmetrical in the adult and bilaterally symmetrical in the larval stage. b) Marine, they migrate towards freshwater for spawning, then their larvae retum to ocean after metamorphosis. c) Triploblastic, bilaterally symmetrical, coelomate and metamerically segmented animals.

From a fish market, you got a fish, on a close watching your friend says it is a cartilaginous fish. a) Which characters helped him to identify it as a cartilaginous fish. (any four characters.) b) Name the class it belongs.