Answer:
C. Transpiration from leaves enters the atmosphere
Step-by-step explanation:
All of the rest are things humans interfere with. Humans build dams that flood ecosystems, mess with rivers so that boats can flow through more easily, deforest tropical areas, and pump groundwater for irrigation. All of these are things us humans do that interfere with the environment and hydrologic cycle. Transpiration of leaves enters the atmosphere is something that is done naturally with no human interference.