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.
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
Which group of chordates possess sucking and circular mouth without jaws?
Cyclostomata. They are also known as the jawless fish.
What is the importance of pneumatic bones and air sacs in Aves?
Pneumatic bones are hollow and hence are light weight. They help to reduce the weight and hence help the birds in flight. They also provide support.