What typically happens to the majority of rainwater that falls to the ground under natural conditions?

Rainwater that falls to the ground under natural conditions generally infiltrates the soil or evaporates. This process is part of the natural water cycle, where precipitation seeps into the ground, replenishing groundwater supplies, or is taken up by plants, which later release water vapor back into the atmosphere through a process called transpiration.

Infiltration plays a critical role in maintaining aquifers and ensuring a sustainable water supply for ecosystems. It can also help in reducing surface runoff, which is crucial in minimizing erosion and pollution that often accompany stormwater flow. Evaporation, on the other hand, contributes to the water cycle by returning moisture to the air, influencing weather patterns and climate.

The other choices imply processes that are not the primary outcomes of rainwater under natural conditions. While water can flow into rivers or create surface puddles during heavy rainfall, these occurrences are secondary effects rather than the predominant ones in a typical scenario. Storing rainwater in reservoirs usually involves human intervention to manage water resources, which is not a natural occurrence. Thus, the most accurate reflection of what happens to the majority of rainwater is that it infiltrates the ground or evaporates.