Water Facts...How much do you know

Producing one litre of milk requires a massive amount of water, primarily to grow the crops and feed that the dairy cows consume. This virtual water footprint is estimated to be around 1000 litres of water per single litre of milk.

At higher altitudes like mountains, atmospheric pressure is lower than at sea level. Since boiling occurs when vapor pressure equals atmospheric pressure, less thermal energy is required to reach this point, causing water to boil at a lower temperature.

Sea water typically has a slightly alkaline pH of around 7.5 to 8.4, whereas natural fresh water is usually closer to neutral (around 6.5 to 7.5) or even slightly acidic due to dissolved organic matter and carbon dioxide.

Unlike most substances, water expands when it freezes because its molecules form a crystalline hexagonal structure held together by hydrogen bonds. This structure takes up more space than liquid water, making ice less dense.

The average residence time of a water molecule in the atmosphere is about 9 to 10 days. After this brief period, it condenses and falls back to Earth as precipitation as part of the global water cycle.

According to global health and development organizations like WHO and UNICEF, approximately 785 to 800 million people lack access to basic clean drinking water services. This represents a major global health and humanitarian challenge.

World Water Day is an annual United Nations observance day held on March 22 to highlight the importance of freshwater and advocate for the sustainable management of freshwater resources.

About 68.7% of the Earth's freshwater is locked up in glaciers, ice caps, and permanent snow (often referred to collectively as icebergs or ice sheets). Only a very small fraction of freshwater is available in liquid form on the surface in rivers and lakes.

Unsafe water, sanitation, and hygiene cause approximately 1.5 to 2 million deaths annually, which translates to roughly 30,000 deaths every week. Children under five in developing countries are the most severely affected by waterborne diseases.

A standard showerhead uses about 15 to 20 litres of water per minute. Therefore, a 10-minute shower typically consumes around 150 to 200 litres, making 190 litres a highly representative average for standard non-low-flow showerheads.

While water covers about 71% of the Earth's surface, about 97% of it is salty ocean water. Of the remaining 3% that is freshwater, over two-thirds is frozen in glaciers and polar ice caps, leaving only about 1% accessible for human consumption.

Blood plasma, which makes up about 55% of blood volume, is roughly 90-92% water. When considering whole blood (including red blood cells, white blood cells, and platelets), water constitutes about 80% of the total composition.

The human brain is composed of approximately 73% to 80% water. Among the given options, 75% is the most accurate representation of this composition.

The human body is made up of approximately 60% to 70% water depending on age, gender, and hydration levels. Among the choices, 70% is the closest standard estimate.

Water has the chemical formula H2O, which means it consists of two hydrogen atoms bonded to one oxygen atom. Therefore, it is made up of oxygen and hydrogen.