The commonest living, which can respire in the absence of `O_(2)` is

Options

A. Fish
B. Yeast
C. Potato
D. Chlorella

Answer

**Step-by-Step Solution:**

1. **Understand the Types of Respiration**:
- There are two main types of respiration: aerobic and anaerobic.
- Aerobic respiration occurs in the presence of oxygen, while anaerobic respiration occurs in the absence of oxygen.

2. **Identify Anaerobic Respiration**:
- Anaerobic respiration is also known as fermentation.
- During fermentation, glucose is broken down into alcohol and carbon dioxide.

3. **Determine Common Organisms for Anaerobic Respiration**:
- The most common organism that carries out anaerobic respiration (fermentation) is yeast.
- Yeast is widely used in the production of alcoholic beverages and bread due to its ability to ferment sugars.

4. **Conclude the Answer**:
- Therefore, the commonest living organism that can respire in the absence of oxygen is yeast.

**Final Answer**: Yeast

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