Final answer:
Bedrock is the solid rock that lies beneath the soil and serves as the foundation for soil formation and terrestrial ecosystems.
Step-by-step explanation:
The term used to describe the solid rock that lies beneath the soil is known as bedrock. Bedrock constitutes the C-horizon layer of soil, which contains the parent material. This layer represents the transition between the soil and the solid rock underneath. Bedrock is a crucial component of the Earth's crust, embodying the foundation upon which soil and various ecosystems are established.
While soil is composed of eroded rock, minerals, organic matter, and other materials, it is the bedrock that gives origin to mineral soils through the process of weathering, adopting a similar composition to the original rock from which it was formed. It serves as the soil base and plays a fundamental role in the formation of soil structure and the ecosystems that depend on it.