Everyday Science

Folic acid is the synthetic form of Vitamin B9, which is essential for DNA synthesis and cell growth. Therefore, Vitamin B9 is correctly identified as folic acid.

The gases commonly used in different types of welding include oxygen, acetylene, and argon. Oxygen and acetylene are used in oxy-acetylene welding, while argon is used as a shielding gas in processes like TIG welding. Hydrogen and nitrogen are not typically used as primary welding gases.

The average distance between the Earth and the Sun is called an Astronomical Unit (AU), which is approximately 149.6 million kilometers. This unit is commonly used in astronomy to describe distances within our solar system.

One carat is internationally defined as exactly 0.2 grams, which is the standard unit of mass used for gemstones and pearls.

The Earth is closest to the Sun (perihelion) in early January, making January the correct answer. This is a well-established astronomical fact.

Spray bottles work based on Bernoulli's Principle, where the fast-moving air over the nozzle creates a pressure difference that draws the liquid up and sprays it out as a fine mist.

The activity of the brain is recorded by an EEG (Electroencephalogram), which measures electrical activity in the brain. ECG records heart activity, X-Ray is used for imaging bones and other structures, and 'None of these' is incorrect.

Vitamin B is a water-soluble vitamin, unlike Vitamins A, D, and E which are fat-soluble. Therefore, Vitamin B is the correct answer as it is not fat-soluble.

Rifampicin is an antibiotic known to cause red or orange discoloration of urine as a side effect. The other options do not typically cause this effect.

When our eyes are closed, we often perceive a uniform dark gray color known as eigengrau, which is the color of the visual noise produced by the retina in the absence of light.