Young lampreys after metamorphosis

Options

A. migrate back to fresh water
B. migrate back to ocean
C. die in fresh water
D. die in ocean

Answer

**Step-by-Step Solution:**

1. **Understanding Metamorphosis in Lampreys**:
- After metamorphosis, young lampreys undergo significant changes in their body structure and behavior. This stage is crucial for their development.

2. **Migration to the Ocean**:
- Once they have completed metamorphosis, young lampreys migrate back to the ocean. This migration is essential for their growth and development.

3. **Duration in the Ocean**:
- They typically remain in the ocean for about three to four years. During this time, they continue to grow and mature.

4. **Return to Freshwater**:
- After spending several years in the ocean, mature lampreys will migrate back to freshwater rivers to spawn. However, it is important to note that they die after this spawning process.

5. **Evaluating the Options**:
- Option A: They migrate back to freshwater - Incorrect.
- Option B: They migrate back to the ocean - Correct.
- Option C: They die in freshwater - Incorrect.
- Option D: (Not specified in the transcript) - Incorrect.

6. **Conclusion**:
- The correct answer to the question about what young lampreys do after metamorphosis is that they migrate back to the ocean.