Which of the following organelles is absent in human sperm?

Options

A. Nucleus
B. Mitochondria
C. Centriole
D. Endoplasmic reticulum

Answer

To solve the question "Which of the following organelles is absent in human sperm?", we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Identify the Organelles**: The question provides four organelles to consider:
- Nucleus
- Mitochondria
- Centriole
- Endoplasmic Reticulum

2. **Analyze the Nucleus**:
- The nucleus is present in human sperm. It contains the genetic material (DNA) necessary for fertilization.
- **Conclusion**: Nucleus is not the correct answer.

3. **Analyze the Mitochondria**:
- Mitochondria are present in human sperm. They provide the energy required for the sperm to swim and reach the egg.
- **Conclusion**: Mitochondria are not the correct answer.

4. **Analyze the Centriole**:
- Centrioles are present in human sperm. They play a crucial role in the formation of the flagellum, which is essential for sperm motility.
- **Conclusion**: Centrioles are not the correct answer.

5. **Analyze the Endoplasmic Reticulum**:
- The endoplasmic reticulum is generally absent in mature human sperm. This is because sperm cells undergo a process of maturation where many organelles are discarded to streamline the cell for its primary function of fertilization.
- **Conclusion**: Endoplasmic reticulum is the correct answer as it is absent in human sperm.

### Final Answer:
The organelle that is absent in human sperm is **Endoplasmic Reticulum**.

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