What fraction of the Earth's surface is covered with water?

The correct answer reflects a well-established scientific fact: approximately 71% of the Earth's surface is covered by water, which is about three-fourths. This high percentage includes oceans, seas, lakes, rivers, and other bodies of water. When considering these figures in terms of fractions, three-fourths represents a close estimation of the total water surface coverage.

The other options present different fractions that do not accurately represent this significant proportion. For example, one third (roughly 33%) and two fifths (about 40%) are notably lower than the actual coverage, while nine tenths (90%) greatly exceeds the correct estimate. Understanding these figures is essential when discussing Earth's hydrosphere and the distribution of natural resources, as it highlights the predominance of water on our planet.