Explain whether water is a cause of either chemical weathering, physical weathering or both

Both

Explanation:

because water can fall in holes in rocks and then freeze (expanding) physically weathering the rock. However water can also chemically react with other elements and substances to wear something away. also another chemical weathering that can happen is OXIDATION.

explanation:

for  example, forests have higher evapotranspiration than other ecosystems,  such  as grasslands, because of their deeper roots and greater leaf area. thus forests have a net moistening effect on the atmosphere and become a moisture source for downwind ecosystems.