WEATHERING AND ORGANIC PROCESSES FORM SOIL.
4.2 Reinforcing Key Concepts
BIG IDEA Natural
forces break rocks apart and form soil, which supports life.
KEY CONCEPT Weathering and organic processes form soil.
Soil is a mixture of weathered rock particles and other materials. The diagram below shows
the main soil horizons—A, B, and C—in a soil profile. In the space provided, describe each
Climates and landforms affect soil. Different kinds of soils form in different locations. In
the chart below, compare and contrast arctic soil with desert soil.
The activities of organisms affect soil. For each type of organism below, give one example
and explain how that organism affects the soil.
Properties of soil can be observed and measured. Observations and tests of soil samples
reveal what nutrients the soils contain and therefore what kinds of plants will grow best in
them. What are four properties of soil that can be observed and measured?
Weathering and Soil Formation
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EARTH’S SURFACE, CHAPTER 4, REINFORCING KEY CONCEPTS 237
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