Erythrocytes can carry out anaerobic respiration only because they `"_____________"`.

Answer

To answer the question "Erythrocytes can carry out anaerobic respiration only because they __________", we can follow these steps:

### Step-by-Step Solution:

1. **Identify Erythrocytes**: Erythrocytes are also known as red blood cells (RBCs). They are responsible for transporting oxygen from the lungs to the body tissues and returning carbon dioxide from the tissues back to the lungs.

2. **Understand Cellular Respiration**: Cellular respiration can be aerobic or anaerobic. Aerobic respiration requires oxygen and occurs in the mitochondria, while anaerobic respiration does not require oxygen and occurs in the cytoplasm.

3. **Mitochondria Presence**: Erythrocytes lack mitochondria. This is a crucial point because mitochondria are the organelles where aerobic respiration takes place, including the Krebs cycle.

4. **Implication of Lack of Mitochondria**: Since erythrocytes do not have mitochondria, they cannot perform aerobic respiration. Therefore, they rely solely on anaerobic respiration to generate ATP (energy).

5. **Conclusion**: Erythrocytes can carry out anaerobic respiration only because they lack mitochondria.

### Final Answer:
Erythrocytes can carry out anaerobic respiration only because they **lack mitochondria**.

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