Question

Flame cells and metagenesis are found respectively in:

• A. Taenia and Hydra
• B. Ascaris and Starfish
• C. Taenia and Obelia
• D. Earthworm and Obelia

Answer 1

Answer: (C)

Metagenesis (or alternation of generation):
- Coelenterates exhibit two body forms - polyp and medusa.
- Polyp = Sessile and cylindrical like Hydra, Adamsia.
Medusa = Free swimming, umbrella-shaped like Aurelia (jellyfish).
- Those cnidarians in which both polyp and medusa alternate with each other, are said to exhibit metagenesis.
Example - Obelia.
Platyhelminthes: They have specialised cells called
flame cells help in osmoregulation and excretion. Examples: Taenia (Tapeworm), Fasciola (Liver fluke).