Everyday Science

Water-soluble vitamins are not stored in the body and excess amounts are excreted primarily through urine, which helps regulate their levels and prevent toxicity.

Titanium is often called the "metal of hope" because of its strength, corrosion resistance, and wide range of applications, symbolizing durability and optimism for future technologies.

Venus is the only planet in our solar system named after a female figure, specifically the Roman goddess of love and beauty. The other planets are named after male gods or mythological figures.

Gobar gas, also known as biogas, primarily consists of methane, which is produced by the anaerobic digestion of organic matter such as cow dung. Methane is the chief constituent responsible for its combustible properties.

The main use of salt in the diet is to increase the taste or flavor of food. Salt (sodium chloride) is widely used as a flavor enhancer, making food more palatable. While salt does provide chloride ions necessary for the production of hydrochloric acid in the stomach, this is a physiological function rather than the main dietary use. Salt is also used in cooking and food preservation, but its primary recognized role in the diet is flavor enhancement.

Most bacteria are killed at temperatures above 140°F (60°C). Among the given options, 149°F is the temperature at which bacteria are effectively killed, making option C correct.

Chlorophyll contains magnesium as its central metal ion, which is essential for its role in photosynthesis. This distinguishes it from other pigments that may contain different metals.

Night vision devices work by detecting infrared rays, which are emitted as heat by objects and are invisible to the naked eye. This allows seeing in the dark by converting infrared radiation into visible images.

The winter solstice in the Southern Hemisphere occurs around 22 December, marking the shortest day and longest night of the year there. This is when the Southern Hemisphere is tilted furthest away from the Sun.

Hydrogen is not considered a greenhouse gas because it does not absorb infrared radiation significantly, unlike methane, nitrous oxide, and carbon dioxide, which are well-known greenhouse gases contributing to the greenhouse effect.