Name an animal which excretes cell waste in gaseous form (ammonia) which directly dissolves in water.

Answer

**Step-by-Step Solution:**

1. **Understanding Excretion in Animals**: Excretion is the process by which animals eliminate waste products from their bodies. Different animals have different methods of excretion based on their habitat and physiology.

2. **Identifying Waste Products**: The primary waste product of protein metabolism in many aquatic animals is ammonia. Ammonia is highly toxic and needs to be excreted quickly.

3. **Aquatic Animals and Ammonia**: Fish, which are aquatic animals, excrete ammonia directly into the water. This is because ammonia is soluble in water and can be diluted quickly, reducing its toxicity.

4. **Conclusion**: Therefore, the animal that excretes cell waste in the form of ammonia, which directly dissolves in water, is the fish.

**Final Answer**: Fish

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