I'd think that'd be the Myelin Sheath
Mutualism is an association between organisms of two different species in which each benefits. Mutualistic arrangements are most likely to develop between organisms with widely different living requirements. In this case; The Lichens growing on the soil, stabilizes the sand so erosion does not occur supplies nitrogen through fixation. Destruction caused by humanity.
Biodiversity is the variety of plants, animals and ecosystems in the world, it is a measure of our planet's health. Overexploitation of species, habitat destruction, and the introduction of invasive species are threatening Earth's biodiversity.
