In which era, did life originate?

Options

A. Precambrian
B. Proterozoic
C. Mesozoic
D. Cenozoic

Explanation

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks in which era life originated.

2. **Understand the Geological Time Scale**: The geological time scale is divided into several eras, including the Precambrian, Paleozoic, Mesozoic, and Cenozoic.

3. **Focus on the Precambrian Era**: The Precambrian era is the earliest part of Earth's history, spanning from the formation of the Earth about 4.6 billion years ago to about 600 million years ago. This era is significant because it is when life first appeared.

4. **Recognize the First Living Organisms**: During the Precambrian era, the first living organisms, such as cyanobacteria, emerged. These organisms played a crucial role in producing oxygen through photosynthesis, which eventually made the Earth’s environment suitable for more complex life forms.

5. **Conclusion**: Based on the information, the era in which life originated is the Precambrian era.

**Final Answer**: Life originated in the Precambrian era.

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