No rupture and friction occur in water column of vessels and tracheids during ascent of sap. It is due to

Options

A. they are lignified thick walls
B. they have weak gravitational pull
C. cohesion and adhesion
D. transpiration pull

Answer

To answer the question regarding why there is no rupture and friction in the water column of vessels and tracheids during the ascent of sap, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of Vessels and Tracheids**:
- Vessels and tracheids are specialized structures in plants that facilitate the transport of water and nutrients. They have thick, lignified walls which provide structural support.

**Hint**: Consider the role of structural features in preventing physical damage.

2. **Cohesion of Water Molecules**:
- Water molecules exhibit a property known as cohesion, which is the attraction between water molecules themselves. This strong cohesive force helps maintain a continuous column of water.

**Hint**: Think about how water behaves at a molecular level and how this affects its movement.

3. **Adhesion to Vessel Walls**:
- In addition to cohesion, water molecules also exhibit adhesion, which is the attraction between water molecules and the walls of the vessels and tracheids. This helps the water to stick to the walls and prevents it from breaking away.

**Hint**: Reflect on how the interaction between water and the walls of the vessels contributes to the stability of the water column.

4. **Role of Transpiration Pull**:
- The process of transpiration creates a negative pressure in the leaves, which pulls water upward through the xylem vessels. This pull is facilitated by both cohesion and adhesion, ensuring that the water column remains intact.

**Hint**: Consider how the loss of water from leaves influences the movement of water in the plant.

5. **Conclusion**:
- The absence of rupture and friction in the water column during the ascent of sap is primarily due to the cohesive forces between water molecules and the adhesive forces between water molecules and the vessel walls. Thus, the correct answer to the question is option C: "because of cohesion and adhesion."

### Final Answer:
The correct answer is C: because of cohesion and adhesion.