Earthworms are -
- Uricotelic when plenty of water is available
- Ammonotelic when plenty of water is available
- Ureotelic when plenty of water is available
- Uricotelic under conditions of water scarcity
Answer
(2) Ammonotelic when plenty of water is available
Solution
As per NCERT, excretion of ammonia (ammonotelism) needs a large amount of water, because ammonia is highly toxic and very soluble.
⇒ Earthworms excrete through nephridia; when plenty of water is available they excrete mainly ammonia (ammonotelic).
⇒ Under water scarcity they switch mainly to urea (ureotelic), not uric acid.
∴ Earthworms are ammonotelic when plenty of water is available.
Answer: (2)