A marine dinosaur is

Options

A. Ichthyousaur
B. Pelycosaur
C. Pterosaur
D. Tryrannosaurus.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks to identify a marine dinosaur from the given options.

2. **Reviewing the Options**:
- Option 1: Ichthyosaur
- Option 2: Palaeosaur
- Option 3: Pterosaur
- Option 4: Trirhinosaur

3. **Identifying Marine Dinosaurs**:
- Ichthyosaurs are known as marine reptiles that lived during the Mesozoic era. They are often referred to as marine dinosaurs due to their aquatic lifestyle.
- The other options need to be evaluated to determine if they are marine or land animals.

4. **Analyzing Each Option**:
- **Ichthyosaur**: This is indeed a marine reptile, belonging to the order Ichthyopterygia. They thrived in the oceans and are characterized by their fish-like appearance.
- **Palaeosaur**: This is a land animal, not a marine dinosaur.
- **Pterosaur**: This is a flying reptile, also not a marine dinosaur.
- **Trirhinosaur**: This is another land animal and does not fit the criteria for a marine dinosaur.

5. **Conclusion**: Based on the analysis, the only marine dinosaur among the options is the **Ichthyosaur**.

**Final Answer**: The correct answer is **Ichthyosaur**.

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