The fruit walls of nuts are hard due to

Options

A. Fibres
B. Parenchyma
C. Sclereids
D. `CaCO_(3)` crystals

Answer

To answer the question "The fruit walls of nuts are hard due to," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of Nuts**:
- Nuts are a type of fruit that typically have a hard outer shell. This shell is what we refer to as the fruit wall.

2. **Identifying the Components of Fruit Walls**:
- The fruit walls of nuts are made up of various types of cells and tissues. To determine what makes them hard, we need to look at the specific types of cells present.

3. **Analyzing the Options**:
- **Fibers**: These are elongated cells that provide support but are not primarily responsible for the hardness of the fruit wall.
- **Parenchyma**: This tissue is generally soft and found in the softer parts of plants, so it does not contribute to the hardness of nuts.
- **Sclerite**: These are specialized cells that can be spherical, oval, or cylindrical with narrow lumens. Sclerites are known for their hardness and are commonly found in the fruit walls of nuts.
- **CaCO3 Crystals**: While these crystals are present in some plants, they are not the main reason for the hardness of nut fruit walls.

4. **Conclusion**:
- Based on the analysis, the correct answer is that the fruit walls of nuts are hard due to **sclerite** cells.

### Final Answer:
The fruit walls of nuts are hard due to **sclerite**.

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