Scientists observed that over the past 40 years, marmots (types of squirrels) are located at increasing elevations on mountains. what is the best explanation for this observation?

This could signify Climate Change. Marmots hibernate during winter hence require snow and ice. Therefore, the plausible explanation for their increasing numbers up the mountain is due to increased temperatures in their normative hibernation elevation on the mountain.  

your the dumbest b**tch ive ever seen

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.