The principle by which blotting paper absorbs water is
(a) Capillary action
(b) Transpiration pull
(c) Root pressure
(d) Absorptive capacity

Options

A. Capillary action
B. Transpiration pull
C. Root pressure
D. Absorptive capacity

Answer

To solve the question regarding the principle by which blotting paper absorbs water, we need to analyze the given options one by one.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the principle that allows blotting paper to absorb water.

2. **Option A - Capillary Action**:
- Capillary action refers to the ability of a liquid to flow in narrow spaces without the assistance of external forces. This phenomenon occurs due to the adhesive forces between the liquid and the solid surface, as well as the cohesive forces within the liquid itself.
- Blotting paper is made up of fine fibers that create small spaces (capillaries) which allow water to be pulled upwards through these spaces. This is the primary mechanism by which blotting paper absorbs water.

3. **Option B - Transpiration Pull**:
- Transpiration pull is a process that occurs in plants where water is pulled up from the roots to the leaves due to the loss of water vapor from the leaves. This process requires living cells and is not applicable to inanimate objects like blotting paper.

4. **Option C - Root Pressure**:
- Root pressure is the pressure exerted in the roots of plants that helps in the upward movement of water. It is a physiological process that occurs in living plants and does not relate to the absorption of water by blotting paper.

5. **Option D - Absorptive Capacity**:
- Absorptive capacity refers to the ability of a material to absorb a substance. While it describes a property of materials, it does not explain the mechanism by which water is absorbed.

6. **Conclusion**: After analyzing all the options, the correct answer is **(a) Capillary action**. This is the principle that explains how blotting paper absorbs water.

### Final Answer:
The principle by which blotting paper absorbs water is **(a) Capillary action**.

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