Washing down of materials in the soil from upper strata is called

Options

A. Eluviation
B. Illuviation
C. Pedogenesis
D. Weathering

Answer

### Step-by-Step Solution:

1. **Understanding the Concept**: The question asks about the process of washing down materials in the soil from the upper strata. This involves the movement of soil components due to water or other natural forces.

2. **Identifying Key Terms**:
- **Eluvation**: This term specifically refers to the process of washing down materials from the upper layers of soil.
- **Pedogenesis**: This is the process of soil formation, which encompasses various factors including weathering and organic activity.
- **Weathering**: This refers to the breakdown of rocks and minerals into smaller particles, which is a precursor to soil formation.

3. **Analyzing the Options**:
- The question provides three terms: eluvation, pedogenesis, and weathering.
- Among these, eluvation is the most accurate term for the washing down of materials from the upper strata.

4. **Conclusion**: Based on the definitions and the context provided, the correct answer to the question is **eluvation**.

### Final Answer:
The washing down of materials in the soil from upper strata is called **eluvation**.

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