Land reptiles that went back into water evolve into fish-like reptiles probably 200 mya. Example of such reptile is:

Options

A. Tyrannosaurus rex
B. Ichthyosaurs
C. Archaeopteyx
D. Stegosaurus

Answer

To solve the question about which land reptiles evolved back into water and became fish-like reptiles around 200 million years ago, we can analyze the options provided step by step.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for an example of land reptiles that returned to the water and evolved into fish-like reptiles approximately 200 million years ago.

2. **Analyzing Option 1: Tyrannosaurus Rex**:
- Tyrannosaurus Rex (T. rex) is known as one of the largest carnivorous dinosaurs.
- It lived on land and did not evolve into a fish-like reptile.
- **Conclusion**: T. rex is not the correct answer.

3. **Analyzing Option 2: Ichthyosaurs**:
- The term "Ichthyosaur" means "fish lizard," indicating a fish-like reptile.
- Ichthyosaurs evolved from land reptiles that returned to the water around 200 million years ago.
- They are indeed the correct example of the reptiles described in the question.
- **Conclusion**: Ichthyosaurs are the correct answer.

4. **Analyzing Option 3: Archaeopteryx**:
- Archaeopteryx is known as a transitional fossil between dinosaurs and birds.
- It had feathers and lived around 150 million years ago, not 200 million years ago.
- **Conclusion**: Archaeopteryx is not the correct answer.

5. **Analyzing Option 4: Stegosaurus**:
- Stegosaurus was a dinosaur known for its distinctive back plates.
- It was a land-dwelling dinosaur and did not evolve into a fish-like reptile.
- **Conclusion**: Stegosaurus is not the correct answer.

### Final Answer:
The correct answer is **Ichthyosaurs**.

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