Earthworms are commonly

Options

A. Ureotelic when plenty of water is available
B. Uricotelic when plenty of water is available
C. Uricotelic under conditions of water scarcity
D. Ammonotelic when plenty of water is available

Answer

**Step-by-Step Solution:**

1. **Understanding the Terms:**
- **Ammonotelic:** Organisms that excrete ammonia as their primary nitrogenous waste.
- **Ureotelic:** Organisms that excrete urea as their primary nitrogenous waste.
- **Uricotelic:** Organisms that excrete uric acid as their primary nitrogenous waste.

2. **Conditions for Excretion:**
- Ammonia is highly toxic and requires a large amount of water to be safely excreted.
- Urea is less toxic than ammonia and requires less water for excretion.
- Uric acid is even less toxic and can be excreted with minimal water.

3. **Earthworm's Excretion Mechanism:**
- When earthworms are in an environment with plenty of water, they excrete ammonia (ammonotelic).
- In conditions of water scarcity, earthworms switch to excreting urea (ureotelic) to conserve water.

4. **Conclusion:**
- Earthworms are commonly ammonotelic when plenty of water is available, and they become ureotelic when water is scarce.

**Final Answer:**
Earthworms are commonly ammonotelic when plenty of water is available.

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