Jawless fish probably evolved around

Options

A. 500 mya
B. 350 mya
C. 320 mya
D. 200 mya

Answer

To determine when jawless fish probably evolved, we can analyze the provided options and the timeline of evolutionary history.

### Step-by-Step Solution:

1. **Understanding the Timeline of Evolution**:
- The first life forms appeared around 2000 million years ago (MYA).
- Before 500 million years ago, only invertebrates existed.

2. **Identifying Key Evolutionary Milestones**:
- Around 500 million years ago, the Cambrian explosion occurred, leading to a significant increase in the diversity of life, particularly invertebrates.
- It is important to note that jawless fish are considered the first vertebrates in evolutionary history.

3. **Evaluating the Options**:
- The options given are:
- 500 million years ago
- 350 million years ago
- 320 million years ago
- 200 million years ago
- Since jawless fish are the first vertebrates, we need to identify the time frame in which they likely evolved.

4. **Finding the Correct Answer**:
- Based on evolutionary history, jawless fish are believed to have evolved around **350 million years ago**.
- This aligns with the understanding that they were among the earliest vertebrates to appear.

5. **Conclusion**:
- Therefore, the correct answer to the question "Jawless fish probably evolved around" is **350 million years ago**.

### Final Answer:
**Jawless fish probably evolved around 350 million years ago.**

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