During passive absorption, water is absorbed as a result of tension created by.......................................

Explanation

**Step-by-Step Solution:**

1. **Understanding Passive Absorption**: Passive absorption refers to the process by which water is absorbed by plant roots without the use of energy (ATP). This process occurs along the concentration gradient, meaning water moves from an area of higher concentration to an area of lower concentration.

2. **Role of Concentration Gradient**: In passive absorption, water moves from the soil (where it is in higher concentration) into the roots (where it is in lower concentration). This movement does not require energy since it is a downhill movement.

3. **Tension Creation**: The main force that drives passive absorption is the tension created in the aerial parts of the plant. This tension is primarily due to the process of transpiration, which is the loss of water vapor from the leaves and stems of the plant.

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