Soil is a complex mixture of minerals, water, air, organic matter, and countless organisms that are the decaying remains of once
-living things. Soil covers the ground and is an important ingredient for plant growth. However, soil must be formed. The picture shows the soil formation process.
Which statement best describes the process of soil formation?
A) Rain gets into cracks in rocks. When the rain freezes, ice forms. Rocks begin to erode and decay. These processes provide organic and mineral matter for soil.
B) Rain gets into cracks in rocks. When the rain freezes, it fills the cracks with ice. The water dissolves the minerals in the rock, releasing them into the soil.
C) Rain gets into cracks in rocks. When the rain freezes, the cracks expand. The ice preserves dead organic materials. These processes release minerals into the soil.
D) Rain gets into cracks in rocks. When the rain freezes, the cracks expand. The rock begins to break down by the process of weathering, releasing minerals into the soil. Small plants and microorganisms also loosen the rock and when decayed, provide organic material.
