A cross section at the midpoint of the middle piece of a human sperm will show

Options

A. centriole, mitochondria and `9+2` arrangement of microtubules
B. centriole and mitochondria
C. mitochondria and `9+2` arrangement of microtubules
D. `9+2` arrangement of microtubules only.

Explanation

To answer the question regarding what a cross-section at the midpoint of the middle piece of a human sperm will show, we can break down the solution into the following steps:

### Step-by-Step Solution:

1. **Understanding the Structure of Sperm**:
- A human sperm consists of three main parts: the head, middle piece, and tail. The head contains the nucleus and acrosome, while the tail is responsible for motility.

**Hint**: Remember that the sperm is divided into three distinct regions, each with specific functions.

2. **Focusing on the Middle Piece**:
- The middle piece is located between the head and the tail. It is primarily known for being rich in mitochondria, which provide the energy necessary for sperm motility.

**Hint**: Think about what the sperm needs to do (swim) and what provides that energy.

3. **Identifying Key Components in the Middle Piece**:
- In a cross-section of the middle piece, you will find a central bundle of microtubules arranged in a "9 plus 2" formation, which is typical of cilia and flagella. This arrangement consists of 9 doublet microtubules surrounding 2 central microtubules.

**Hint**: Recall the structure of cilia and flagella; they share a similar microtubule arrangement.

4. **Arrangement of Mitochondria**:
- The mitochondria are coiled around this central bundle of microtubules. Their presence is crucial as they supply ATP (energy) for the sperm's movement.

**Hint**: Think about why mitochondria are important for any cell, especially for a cell that needs to be mobile.

5. **Conclusion**:
- Therefore, a cross-section at the midpoint of the middle piece of a human sperm will show both mitochondria and the "9 plus 2" arrangement of microtubules.

**Hint**: Combine your observations about the energy needs of the sperm and the structural components found in the middle piece.

### Final Answer:
A cross-section at the midpoint of the middle piece of a human sperm will show mitochondria arranged around a central bundle of microtubules in a "9 plus 2" arrangement.