Those microscopic organisms perform what 2 processes that help pave the way for lichen by creating organic material.

Decomposition pf residues and weathering of rock.

Explanation:

Microorganisms performs two processes such as decomposition and weathering of rock materials. These two processes make the medium suitable for the growth and development of the lichens because these processes increases nutrient and organic matter on the rock surface that is used by the lichens for its growth. In decomposition process, larger compounds are broken down into simpler substances while on the other hand, the weather of rocks causes breakdown of rock material into simpler minerals that also used by the lichens.

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