Everyday Science

Vitamins help protect the body from diseases by supporting the immune system and maintaining overall health. Minerals and carbohydrates do not primarily serve this protective function.

The lungs are protected by the ribcage, a bony structure that surrounds the chest cavity, providing protection and support to the delicate lung tissues.

The Aurora Borealis is commonly known as the Northern Lights because it occurs in the northern hemisphere near the Arctic Circle.

The concentration of carbon dioxide (CO2) in Earth's atmosphere is approximately 0.03 to 0.04%, which corresponds to about 300 to 400 parts per million (ppm). This makes option A the correct choice.

Wireless transmission can be carried out using various types of electromagnetic waves including infrared waves, radio waves, and microwaves, making 'All of these' the correct answer.

Snow does not melt all at once because it requires a significant amount of energy to change from solid to liquid without a temperature change, due to its high latent heat of fusion. This means the snow absorbs heat while melting, preventing it from melting instantly.

Pure limestone is primarily composed of calcium carbonate (CaCO3), which is the main chemical constituent of limestone. Therefore, the correct answer is Calcium Carbonate.

A Geiger counter is an instrument used to detect and measure ionizing radiation, commonly referred to as radioactivity. It does not measure pressure or water flow.

Potassium nitrate is commonly used as a fertilizer because it provides essential nutrients like potassium and nitrogen to plants, promoting healthy growth.

Vitamin D deficiency leads to poor calcium absorption, causing bone diseases such as osteoporosis and increased risk of fractures.

The three elements with the highest percentage by mass in the human body are oxygen (~65%), carbon (~18.5%), and hydrogen (~10%). Calcium is much less abundant, about 1.5%. Therefore, carbon is the element with the third highest percentage in the human body after oxygen and hydrogen. The option stating calcium at 75% is incorrect and not supported by scientific data.

Police officers commonly use radar guns that emit radio waves to measure the speed of approaching vehicles. The radio waves reflect off the car, and the change in frequency is used to calculate speed.

A fathom is a unit of length commonly used to measure the depth of water and is equal to 6 feet. This is a standard measurement in nautical contexts.

Perspiration primarily helps regulate body temperature by releasing sweat, which cools the body as it evaporates. This is the main physiological function of sweating.

Vitamins A, D, E, and K are the four fat-soluble vitamins. Vitamins B and C are water-soluble, and 'AOT' is not a vitamin. Therefore, the correct answer is Vitamin K.

The Mohs scale is a scale of mineral hardness used to measure the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. Therefore, it is used to measure hardness.

A fresh egg placed in salt water floats because salt water is denser than fresh water, increasing the buoyant force on the egg. This causes the egg to float rather than sink to the bottom.

A bolometer is an instrument used to measure the power of incident electromagnetic radiation via the heating of a material with a temperature-dependent electrical resistance. It effectively measures heat radiation.

CT scans deliver higher radiation doses compared to standard X-rays, ultrasounds, and MRIs because they use multiple X-ray images to create detailed cross-sectional views. Ultrasound and MRI do not use ionizing radiation, and standard X-rays generally have lower doses than CT scans.

The greatest distance between the Earth and the Sun occurs at aphelion, which is the point in Earth's orbit farthest from the Sun. The other options are either incorrect terms or unrelated.

One tonne is defined as 1000 kilograms. This is a standard unit conversion in the metric system.

Raymond Damadian is credited with inventing the first magnetic resonance imaging (MRI) machine, pioneering the use of NMR technology for medical imaging. The other options are scientists known for different discoveries: Godfrey Hounsfield developed the CT scanner, Matthias Schleiden and Theodore Schwann contributed to cell theory.

Cow's milk typically contains about 87% water, which is the highest percentage among the given options. This high water content is essential for its nutritional and fluid properties.

The Beaufort Scale is the standard measurement scale used to estimate wind speed based on observed conditions, making it the correct answer. The Richter Scale measures earthquake magnitude, and 'Meter-second scale' is not a recognized scale for wind speed.

The term 'Dark side of the Moon' commonly refers to the far side of the Moon that is not visible from Earth, but it is not a specific region like the equator or poles. Therefore, none of the given options correctly identify the 'Dark side'.