The statement "soils were once rocks" means that the soil we see today was formed from the breakdown of rocks over a long period of time. Here's a breakdown:

* Rocks: Rocks are solid, naturally occurring materials made up of minerals. They come in many forms, like granite, limestone, and sandstone.

* Weathering: Rocks are constantly being broken down by natural forces like wind, rain, ice, and temperature changes. This process is called weathering.

* Erosion: The broken pieces of rock are then transported by water, wind, or ice. This process is called erosion.

* Soil Formation: Over thousands or even millions of years, these broken rock pieces, along with decaying organic matter (plants and animals), mix together to create soil.

In summary: The soil we see today is the result of the slow and continuous breakdown of rocks over time. It's a long and complex process, but ultimately, rocks are the raw materials that form soil.