Which one of the following matching pairs is wrong?

Options

A. Mollusca - Pseudocoel
B. Cnidaria - Nematocyst
C. Annelida - Chloragogen cells
D. Echinodermata - Water vascular system

Answer

To determine which of the following matching pairs is wrong, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the first option: Mollusca and Pseudocoelomate**
- Mollusca is a phylum that includes animals like snails, clams, and octopuses.
- Molluscs are coelomates, meaning they have a true coelom (body cavity).
- **Conclusion**: This pair is incorrect because Mollusca is not matched with Pseudocoelomate.

2. **Identify the second option: Cnidaria and Nematocyst**
- Cnidaria includes organisms such as jellyfish, corals, and sea anemones.
- Nematocysts are specialized cells found in Cnidarians, used for capturing prey and defense.
- **Conclusion**: This pair is correct.

3. **Identify the third option: Annelida and Glucose Regulating Cells**
- Annelida includes segmented worms like earthworms and leeches.
- The term "glucose regulating cells" is not typically associated with Annelida. Instead, annelids have specialized cells for various functions, but glucose regulation is not a defining feature.
- **Conclusion**: This pair is incorrect.

4. **Identify the fourth option: Echinodermata and Water Vascular System**
- Echinodermata includes starfish, sea urchins, and sea cucumbers.
- The water vascular system is indeed a specialized feature of echinoderms, used for locomotion, feeding, and gas exchange.
- **Conclusion**: This pair is correct.

### Final Conclusion:
The wrong matching pair is **Mollusca and Pseudocoelomate**.