If you were in charge of preserving ancient stone ruins and sculptures in an outdoor environment, ...

 Biodeterioration is important to the overall deterioration of stone materials over time. A complex community of microorganisms develops on the surface and inside the stone material. Fungi and fungi-algae symbioses are thought to have a large role in biodeterioration of stone through the production of oxalic acid, which dissolves minerals. Strategies to prevent deterioration could involve protecting the objects from light (to inhibit the growth of lichens) or application of mild anti-fungal solutions. Any strategies related to decreasing fungal growth are appropriate.