Question

Which among the following is the lowest grade vertebrate?

• A. Agnatha
• B. Cyclostomata
• C. Echinodermates
• D. Both A and B

Answer 1

The correct option is D Both A and B

Agnatha is a superclass of jawless fishes in the phylum Chordata. These are ectothermic, meaning they do not regulate their own body temperature. They show slow metabolism in cold water. They do not have a proper stomach rather they have a long homogenous gut. They are lowest grade vertebrates. The notochord is persistent in them.

Cyclostomata is a group of chordates that comprises the living jawless fishes - the lampreys and hagfishes. These fishes are a parasite as well as scavengers. The body is long, then tubular and tail is flat. They are also known as false fish.

So, the correct answer is option D.