What percentage of all water on Earth is freshwater?

The correct percentage of all water on Earth that is freshwater is approximately 2.5%. Freshwater makes up a small fraction of the total water on the planet, with the vast majority being saltwater found in oceans. This total freshwater includes all water found in glaciers, ice caps, groundwater, and surface water bodies like rivers and lakes.

The figure of 2.5% reflects the general understanding among hydrologists and environmental scientists about the distribution of Earth's water resources. The small percentages presented in the other choices do not represent the true proportion of freshwater. For instance, while 0.5%, 0.009%, and 1% may seem like plausible numbers at a glance, they grossly underestimate the actual amount of freshwater available on Earth, which is significantly higher at around 2.5%. Thus, correctly identifying the percentage of Earth's water that is freshwater is crucial for understanding water resource management and conservation efforts.