Here's why:

* Weathering: This process breaks down rocks into smaller pieces through physical and chemical processes like freezing/thawing, abrasion, and chemical reactions.

* Mineral Matter: The broken-down rock fragments, containing various minerals, become part of the soil. These minerals provide essential nutrients for plant growth.

While soil contains other components like organic matter (from decomposed plant and animal material), air, and water, mineral matter forms the foundational base of soil, originating from the parent rock.