_ growing on rocks breaks them, setting the stage for other organisms during ecological succession.

Explanation

Lichens growing on rocks breaks them, setting the stage for other organisms during the course of ecological succession.Lichens are a symbiotic relationship between a fungus and an alga. The fungus provides the alga with water and minerals, and the alga provides the fungus with food. Lichens are able to grow on bare rock because they secrete acids that break down the rock. This process is called lichenolysis.As lichens break down the rock, they create a small pocket of soil. This soil provides a habitat for other organisms, such as mosses and small plants. These organisms further break down the rock, creating more soil. This process continues until a mature ecosystem is established.Lichens are therefore important pioneer species in ecological succession. They are the first organisms to colonize bare rock, and they set the stage for the establishment of other organisms.