Which of the following is not example of osmosis ?

Options

A. Water passing from root hair to adjacent cells.
B. Water passing up a xylem element to anther element above it.
C. Water entering mesophyll cell from the xylem elements.
D. Water entering the root hair from the soil.

Answer

To determine which of the following options is not an example of osmosis, we will analyze each option based on the definition of osmosis and the processes involved.

### Step-by-Step Solution:

1. **Understanding Osmosis**:
- Osmosis is the movement of water molecules through a semi-permeable membrane from an area of lower solute concentration to an area of higher solute concentration until equilibrium is reached.

2. **Analyzing the Options**:
- **Option 1**: Water passing from root hair to adjacent cells.
- This is an example of osmosis because water moves from the area of higher water concentration (in the soil) to the area of lower water concentration (in the root hair cells).

- **Option 2**: Water passing from xylem element to another element above it.
- This is **not** an example of osmosis. Water movement in xylem is primarily due to cohesive forces and transpiration pull, not osmosis. The xylem vessels are long and do not involve the semi-permeable membrane process characteristic of osmosis.

- **Option 3**: Water entering mesophyll cells from the xylem element.
- This is an example of osmosis. Water moves from the xylem (where there is a higher concentration of water) into the mesophyll cells (where there is a lower concentration of water).

- **Option 4**: Water entering the root hair from soil.
- This is also an example of osmosis as water moves from the soil (higher concentration of water) into the root hair cells (lower concentration of water).

3. **Conclusion**:
- The option that is not an example of osmosis is **Option 2**: Water passing from xylem element to another element above it.

### Final Answer:
**Option 2** is not an example of osmosis.

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