Echinoderms are

Options

A. Ammonotelic and aminotelic
B. Ureotelic
C. Uricotelic
D. Both B and C.

Answer

### Step-by-Step Solution:

1. **Understanding Echinoderms**: Echinoderms are a group of marine animals that include species such as starfish, sea urchins, and sea cucumbers. They are characterized by their radial symmetry and a unique water vascular system.

2. **Excretion in Echinoderms**: The question focuses on the method of excretion in echinoderms. Excretion is the process of removing waste products from the body.

3. **Types of Excretion**:
- **Ammonotelism**: This is the process where organisms excrete ammonia directly as a waste product. It is common in aquatic animals because ammonia is highly toxic and needs to be removed quickly. Echinoderms primarily excrete ammonia.
- **Aminotelism**: Some echinoderms, like certain starfish, can excrete excess amino acids. This is a less common method of excretion compared to ammonotelism.
- **Ureotelism**: This involves the excretion of urea. It is not typical for echinoderms since they live in water and can easily excrete ammonia.
- **Uricotelism**: This is the excretion of uric acid, which is also not seen in echinoderms for the same reasons as ureotelism.

4. **Conclusion**: Given that most echinoderms are ammonotelic, and some can be aminotelic, the correct answer to the question is that echinoderms are primarily ammonotelic and can also exhibit aminotelism.

5. **Final Answer**: The correct option is "both ammonotelic and aminotelic."