The size of clay particles is

Answer

To answer the question regarding the size of clay particles, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question is asking for the size of clay particles in comparison to a specific measurement (0.002 millimicrons).

2. **Know the Size Range of Soil Particles**: Soil is composed of different types of particles, primarily sand, silt, and clay. Each of these has a distinct size range:
- Sand particles are the largest.
- Silt particles are medium-sized.
- Clay particles are the smallest.

3. **Identify the Size of Clay Particles**: According to the information provided, clay particles are very small. Specifically, they are defined as being less than 0.002 millimicrons.

4. **Evaluate the Options**: The options given are:
- Less than 0.002 millimicrons
- More than 0.002 millimicrons
- None of the above

5. **Select the Correct Option**: Since clay particles are indeed less than 0.002 millimicrons, the correct answer is the first option: **Less than 0.002 millimicrons**.

### Final Answer:
The size of clay particles is **less than 0.002 millimicrons**.

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