In which geological era did microbes originate

Options

A. Precambrian
B. Proterozoic
C. Azoic
D. Palaeozoic.

Answer

To determine in which geological era microbes originated, we can analyze the options provided:

1. **Precambrian Era**: This era is known for the appearance of hard-shelled organisms, but it is not specific to the origin of microbes. Therefore, this option is incorrect.

2. **Proterozoic Era**: This era is significant because it is during this time that microbes, including bacteria and blue-green algae, first appeared. This makes this option correct.

3. **Erzoic Era**: This term is not commonly used in geological time scales and is often referred to as the age of rocks. Thus, this option is also incorrect.

4. **Paleozoic Era**: This era is characterized by the appearance of the first vertebrate organisms, which does not relate to the origin of microbes. Hence, this option is incorrect as well.

Based on the analysis, the correct answer is the **Proterozoic Era**, where microbes originated.

### Step-by-Step Solution:
1. **Identify the options**: List the geological eras provided in the question.
2. **Analyze each option**:
- **Precambrian**: Known for hard-shelled organisms, not the origin of microbes.
- **Proterozoic**: Known for the appearance of microbes like bacteria and blue-green algae.
- **Erzoic**: Not a standard term; refers to the age of rocks.
- **Paleozoic**: Known for the first vertebrate organisms, not microbes.
3. **Determine the correct answer**: Based on the analysis, the Proterozoic Era is where microbes originated.