World Water Day

Water is unique because it is denser in its liquid state than in its solid state (ice). This is why ice floats on water.

Under standard atmospheric pressure, water boils at 100 degrees Celsius.

The phase change from a solid to a liquid is called melting. Evaporation is liquid to gas, condensation is gas to liquid, and boiling is a specific type of rapid evaporation.

The water cycle is driven by solar energy (causing evaporation) and gravity (causing precipitation to fall and water to flow downhill). Option D correctly identifies gravity's role in moving water from the atmosphere to the ground.

Of the small percentage of Earth's water that is fresh, the vast majority is locked away in ice caps and glaciers, rather than in rivers, lakes, or groundwater.

Aquifers are geological formations of porous rock that are capable of holding and transmitting significant quantities of groundwater.

Mineral water is a mixture containing water and dissolved minerals, not a pure chemical substance. A pure chemical substance consists of only one type of molecule or atom.

The human body is composed of approximately 60-65% water on average. This percentage varies by age and body composition, but 65% is the standard accepted figure in general biology.

Wild waters, often referred to as runoff or sheet wash, are geological agents that model the surface of the earth without being confined to a permanent channel. Other options contain inaccuracies, such as karstic modeling dissolving limestone, not granite.

According to World Health Organization and UN data, approximately 2.1 billion (2100 million) people globally lack access to safely managed drinking water services.

The water cycle interacts with the four main spheres of the Earth: the Geosphere (land), Atmosphere (air), Hydrosphere (water), and Biosphere (living organisms).

Approximately 71% of the Earth's surface is covered by water, primarily in the form of oceans.

Water melts from ice to liquid at 0 degrees Celsius under standard atmospheric pressure.

Surface runoff occurs when excess water flows over the land surface, driven by gravity toward lower elevations. Condensation is caused by cooling, not heating.

The prompt calculates a savings of 350 milliliters, but the unit stated in the conclusion is incorrectly given as litres. Because the unit mismatch makes the final statement mathematically and dimensionally false, the statement is false.

Evaporation is the process where liquid water absorbs thermal energy and turns into water vapor, rising into the atmosphere.

The sun provides the energy for evaporation, while gravity drives the movement of water through infiltration and surface runoff. Option B correctly summarizes these pathways.

The water cycle is a continuous movement of water between the oceans, atmosphere, and land (lakes, rivers, groundwater), eventually returning to the oceans.