Trimethylamine is nitrogenous waste product of marine teleosts.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the Organism**: Marine teleosts are a group of bony fishes that live in marine environments. They have adapted to their surroundings in various ways, including how they excrete nitrogenous waste.

2. **Identifying the Nitrogenous Waste**: The primary nitrogenous waste product produced by marine teleosts is trimethylamine. This compound is a result of the metabolism of nitrogen-containing compounds in the fish.

3. **Comparing Toxicity**: Trimethylamine is classified as a non-toxic nitrogenous waste product. This is in contrast to ammonia, which is highly toxic and is the primary nitrogenous waste in many other fish, particularly freshwater species.

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