First cellular form of life on earth appeared

Options

A. 2000 mya
B. 500 mya
C. 4500 mya
D. 3000 mya

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:** The question asks about the time when the first cellular form of life appeared on Earth. We need to identify the correct time frame from the options provided: 2000 million years ago (Mya), 500 Mya, 4500 Mya, and 3000 Mya.

2. **Reviewing Evolutionary Timeline:** To answer this question, we need to consider the evolutionary timeline of life on Earth. The first cellular forms of life are believed to be simple prokaryotic cells, which emerged long before more complex life forms.

3. **Identifying Key Timeframes:**
- **4500 Mya:** This timeframe is too early for cellular life as it predates the formation of Earth’s crust and oceans.
- **3000 Mya:** This is closer to the emergence of cellular life but still not the earliest.
- **2000 Mya:** This is a significant period in Earth's history when the first cellular forms of life, particularly prokaryotes, are believed to have appeared.

4. **Conclusion:** Based on the evolutionary timeline and the emergence of cellular life, the correct answer is that the first cellular form of life appeared around **2000 million years ago (Mya)**.

**Final Answer:** 2000 Mya

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