Final answer:
Weathering of solid rock is the first step in soil formation, which then allows lichens to grow and contribute to the breakdown of rock, eventually leading to a developed soil that can support a variety of plant life.
Step-by-step explanation:
c) Weathering of solid rock occurs. Soil formation begins with the weathering of rock by natural forces. This process creates the conditions necessary for the establishment of pioneer species that can colonize the new environment.
Lichens are among the first organisms to appear, and they play a crucial role as pioneer species in primary ecological succession. They can grow directly on rocks without soil because of their unique symbiotic relationship between a fungus and a photosynthetic partner, like algae or cyanobacteria. The lichen secretes acids that break down the rock, aiding the process of soil formation.
Over time, as lichens and other pioneer species like mosses grow and die, they contribute organic material to the developing soil, which eventually becomes hospitable for other plant species. This gradual process adds to the complexity of the ecosystem and leads to the development of mature soil layers, with upper horizons rich in organic matter that supports diverse plant growth.