Petromyzon spawns

Options

A. on land
B. in fresh water
C. in seas
D. both (1) & (2)

Answer

### Step-by-Step Solution:

1. **Identify Petromyzon**: Petromyzon is commonly known as sea lampreys. They belong to a group called cyclostomes, which are jawless fish.

2. **Life Cycle Stages**: Petromyzon has a unique life cycle. They spend their early stages in freshwater environments such as streams and rivers.

3. **Middle Stage Habitat**: After the early stages, they migrate to the ocean where they live in saltwater during their middle life stage.

4. **Breeding Behavior**: When it comes time for breeding, Petromyzon returns to freshwater environments. This is crucial for their spawning process.

5. **Spawning and Death**: After they spawn in freshwater, Petromyzon typically dies shortly thereafter.

6. **Conclusion**: Based on the information gathered, Petromyzon spawns in freshwater.

### Final Answer:
Petromyzon spawns in freshwater.