In which one of the following processes the phenomenon of osmosis is not involved ?

Options

A. Water entering a mesophyll cell from xylem vessel element
B. Water passing from root hair to adjacent calls
C. Water from soil entering a root hair
D. Water passing up a xylem vessel element to xylem vessel above it

Answer

To solve the question "In which one of the following processes the phenomenon of osmosis is not involved?", we will analyze each option provided and determine whether osmosis is involved in each process.

### Step-by-Step Solution:

1. **Understand Osmosis**:
- Osmosis is defined as the movement of water (or solvent) from an area of higher concentration of water to an area of lower concentration of water through a semi-permeable membrane.

2. **Evaluate Each Option**:
- **Option 1**: Water entering a mesophyte cell from xylem vessel elements.
- In this process, water moves from the xylem (which has a higher concentration of water) into the mesophyte cell (which has a lower concentration of water). This is a classic example of osmosis.

- **Option 2**: Water passing from root hair to adjacent cell.
- Here, water moves from the root hair (higher concentration of water) to the adjacent cell (lower concentration of water). This process also involves osmosis.

- **Option 3**: Water from the soil entering a root hair.
- In this case, water moves from the soil (which has a higher concentration of water) into the root hair (which has a lower concentration of water). This is again an example of osmosis.

- **Option 4**: Water passing up a xylem vessel element to the xylem vessel above it.
- In this scenario, the movement of water is primarily driven by cohesive forces and capillary action rather than osmosis. The water is not moving from a higher concentration to a lower concentration in the same way as in the previous examples.

3. **Conclusion**:
- The only process in which osmosis is not involved is **Option 4: Water passing up a xylem vessel element to the xylem vessel above it**.

### Final Answer:
**Option 4: Water passing up a xylem vessel element to the xylem vessel above it.**

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