Which one of the following can respire in the absence of oxygen ?

Options

A. Amoeba
B. Tapeworm
C. Housefly
D. Hydra

Answer

To determine which organism can respire in the absence of oxygen, we need to analyze the options provided: amoeba, tapeworm, housefly, and hydra.

### Step-by-Step Solution:

1. **Understanding Anaerobic Respiration**:
- Anaerobic respiration is a type of respiration that occurs without oxygen. Organisms that can perform this type of respiration are known as anaerobic organisms.

2. **Analyzing Each Organism**:
- **Amoeba**: Amoeba is a unicellular organism that has mitochondria, which are the sites of aerobic respiration. It requires oxygen for its survival and energy production.
- **Tapeworm**: Tapeworms are parasitic organisms that live in the intestines of their hosts. They have adapted to survive in low-oxygen environments, such as the human gut, and can perform anaerobic respiration.
- **Housefly**: Houseflies are insects that rely on aerobic respiration, which requires oxygen to break down food and release energy.
- **Hydra**: Hydra is a simple aquatic organism that also relies on diffusion for gas exchange, primarily using oxygen for aerobic respiration.

3. **Identifying the Correct Answer**:
- Among the options, the tapeworm is the only organism that can respire in the absence of oxygen, as it has adapted to survive in anaerobic conditions within the human gut.

### Conclusion:
The correct answer is **Tapeworm**.

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