Question

Pancreas is absent in
A) Amphibia
B) Osteichthyes
C) Chondrichthyes
D) Cyclostomata

Answer 1

Hint: The pancreas is a long, flat gland. It lies in the abdomen behind the stomach. The pancreas is located just behind the stomach within the curve of duodenum. It is divided into three parts: the head, body and tail. It produces enzymes which are released into the small intestine to help with digestion. It also contains clusters of cells called islets.

Complete Answer:
A) Amphibia : Amphibians are the cold-blooded and freshwater vertebrates. Both on land and in water they can live. There are three main groups of amphibians like frogs and toads, salamanders and newts and wormlike caecilians. Hence option A is incorrect.

B) Osteichthyes: Osteichthyes is the class of bony fishes. They include lungfishes, ray-finned fishes and lobe-finned fishes. They are cold blooded vertebrates. They breathe through gills and they use fins for swimming. Hence option B is incorrect.

C) Chondrichthyes: Chondrichthyes is a class of Cartilaginous fishes. It includes sharks, rays and Chimaeras. Chondrichthyes are jawed vertebrates. They include paired fins, a heart with its chambers in series. Hence option C is incorrect.

D) Cyclostomata: They are jawless vertebrates with a class of round mouthed fishes under the superclass Agnatha. The digestive system of Cyclostomata lacks stomach and pancreas. Hence option D is correct.

Hence option D: Cyclostomata is the correct answer.

Note: Pancreas is absent in cyclostomates, a class of Agnatha. The pancreas is derived from the endoderm of embryos. It lies inferior to the stomach in a bend of the duodenum It is both an exocrine and endocrine gland.