Cyanobacteria originated on earth about

Options

A. 4.3-4.8 billion years ago
B. 3.3-3.8 billion years ago
C. 2.3-2.8 billion years ago
D. 1.3-1.8 billion years ago

Answer

**Step-by-Step Solution:**

1. **Identify the Organism**: The question asks about cyanobacteria, which are also known as blue-green algae.

2. **Understand Their Role**: Cyanobacteria are significant because they were the first photosynthetic autotrophs. This means they can produce their own food through photosynthesis.

3. **Impact on the Atmosphere**: One of the critical contributions of cyanobacteria is that they introduced free oxygen into the Earth's atmosphere through the process of photosynthesis.

4. **Determine the Origin Timeframe**: Based on scientific evidence, cyanobacteria are believed to have originated around 3.5 billion years ago.

5. **Select the Correct Option**: Given the options provided, the correct timeframe for the origin of cyanobacteria is approximately 3.3 to 3.8 billion years ago. Therefore, the right answer is option B.

**Final Answer**: Cyanobacteria originated on Earth about 3.3 to 3.8 billion years ago.

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