Bedrock is the solid, unweathered rock that lies beneath the soil. It is the parent material from which soil is formed through a process called weathering. Here's how it works:

1. Weathering: The bedrock is broken down by physical (like freezing/thawing) and chemical (like acid rain) processes into smaller and smaller pieces.

2. Decomposition: Organic matter (dead plants and animals) decomposes on top of the weathered rock, adding nutrients and structure to the developing soil.

3. Soil Formation: Over time, the weathered rock, organic matter, and other materials like minerals and air combine to form soil.

So, while soil itself is a complex mixture, its starting point is the bedrock beneath the surface!