Distinct layers of soil are called horizons while their arrangment is called soil profile.

Answer

**Step-by-Step Solution:**

1. **Understanding Soil Layers**: The distinct layers of soil are referred to as "horizons." Each horizon has different characteristics and compositions. The main horizons typically include the organic layer (humus), topsoil, subsoil, and bedrock.

2. **Identifying the Horizons**:
- **O Horizon**: This is the organic layer, rich in decomposed organic matter (humus), which is dark in color.
- **A Horizon**: Known as the topsoil, it contains a mix of minerals and organic matter.
- **E Horizon**: This layer is often leached of minerals and nutrients.
- **B Horizon**: Also known as subsoil, it accumulates minerals and nutrients that have leached down from above.
- **C Horizon**: This layer consists of weathered parent rock material.
- **R Horizon**: The bedrock layer, which is the solid rock beneath the soil layers.

3. **Defining Soil Profile**: The arrangement of these distinct layers (horizons) from the surface down to the bedrock is called the soil profile. It provides a vertical section of the soil, showing the different layers and their characteristics.

4. **Conclusion**: The statement that "distinct layers of soil are called horizons while their arrangement is called soil profile" is correct. The layers (horizons) are essential for understanding soil composition and health, and their arrangement gives insight into the soil's formation and function.