The ultimate cause for the movement of water against the gravity in a tree is

Options

A. Osmosis
B. transpiration
C. imbibitions
D. photosynthesis

Answer

**Step-by-Step Solution:**

1. **Understanding the Movement of Water in Trees**:
- Water needs to move from the roots of the tree to the leaves, which are often at a higher elevation. This movement occurs against the force of gravity.

2. **Identifying the Mechanism**:
- The process responsible for this upward movement of water is called transpiration.

3. **Explaining Transpiration**:
- Transpiration is the process where water evaporates from the leaves of the tree. As water vapor exits the leaves, it creates a negative pressure (or tension) in the leaf that pulls more water upward from the roots through the xylem vessels.

4. **Role of Cohesion and Adhesion**:
- Water molecules exhibit cohesive properties (they stick to each other) and adhesive properties (they stick to the walls of the xylem vessels). This combination helps maintain a continuous column of water from the roots to the leaves.

5. **Conclusion**:
- Therefore, the ultimate cause for the movement of water against gravity in a tree is transpiration, which creates a pull that helps draw water upward.

**Final Answer**: The ultimate cause for the movement of water against gravity in a tree is transpiration.

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