Name the animal, which exhibits the phenomenon of bioluminescence. Mention the phylum to which it belongs.
Pleurobrachia and Ctenoplana exhibit the phenomenon of bioluminescence. They belong to the phylum Ctenophora
Give one example each of an animal possessing placoid scales and that with cycloid scales.
Placoid scale - are found in Scoliodon
Cycloid scale - are found in Rohu.
Which group of chordates possess sucking and circular mouth without jaws?
Cyclostomata. They are also known as the jawless fish.
What is the role of radula in molluscs?
The radula is a file-like rasping organ found in molluscs. It helps in scraping food. It also used for creating depression in rocks.