Aerenchyma is helpful to plants by -

Options

A. Providing buoyancy in hydrophytes
B. Absorption in stilt roots
C. Giving mechanical strength to plants
D. Giving flexibility to plants.

Answer

### Step-by-Step Solution:

1. **Understanding Aerenchyma**:
- Aerenchyma is a specialized type of parenchyma tissue found in some plants, particularly those that grow in aquatic or waterlogged environments. It is also referred to as aeriferous parenchyma.

2. **Structure of Aerenchyma**:
- This tissue is characterized by large air spaces or cavities that are formed between the cells. These air spaces make the tissue spongy and allow for the easy movement of gases.

3. **Function of Aerenchyma**:
- The primary function of aerenchyma is to facilitate gas exchange (such as oxygen and carbon dioxide) between the plant and its environment. This is particularly important for plants that are submerged in water.

4. **Buoyancy in Hydrophytes**:
- Aerenchyma provides buoyancy to hydrophytes (plants that grow in water) by allowing them to float. The air-filled spaces reduce the overall density of the plant, enabling it to stay afloat on the water surface.

5. **Evaluating Options**:
- Given the options:
1. Providing buoyancy in hydrophytes
2. Absorption in stilt roots
3. Giving mechanical strength to plants
4. Giving flexibility to plants
- The correct answer is option 1: "Providing buoyancy in hydrophytes," as this is a direct function of aerenchyma.