Earthworm are :

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Excretion in Animals:**
- Animals have different methods of excreting nitrogenous waste, which can include ammonia, urea, or uric acid. The method of excretion is often related to the availability of water in their environment.

2. **Definitions of Terms:**
- **Ammonotelic:** Animals that excrete ammonia directly, typically in aquatic environments where water is abundant.
- **Ureotelic:** Animals that convert ammonia to urea for excretion, often in terrestrial environments where water is limited.
- **Uricotelic:** Animals that excrete uric acid, which is less toxic and conserves water, often seen in very arid environments.

3. **Excretion in Earthworms:**
- Earthworms can be classified as both ammonotelic and ureotelic depending on their environmental conditions.
- In aquatic environments, where water is plentiful, earthworms excrete ammonia (ammonotelic).
- In terrestrial environments, particularly when the soil is dry and water is scarce, earthworms convert ammonia to urea for excretion (ureotelic).

4. **Analyzing the Options:**
- **Option 1:** Uricotelic under water scarcity - Incorrect, as earthworms do not excrete uric acid.
- **Option 2:** Ammonotelic when plenty of water is available - Correct, as they excrete ammonia in water.
- **Option 3:** Ureotelic when plenty of water is available - Incorrect, as they do not convert to urea in water-rich environments.
- **Option 4:** Ureotelic when plenty of water is available - Incorrect, as this is a misunderstanding of the conditions.

5. **Conclusion:**
- Based on the analysis, the correct answer is **Option 2: Ammonotelic when plenty of water is available.**

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