What function might the mosses and lichens serve in primary succession

Lichens are typically the first organisms to colonize bare rock. They are therefore the pioneer species in primary succession. Many organisms require soil before they can colonize an area. Lichens that colonize bare rock secrete acids that break down the rock and start the soil-production process.

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he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?