Everyday Science

Caries refers to tooth decay, which is treated by a dentist. Therefore, if you have caries, you should consult a dentist.

Vitamin C is primarily found in fruits and vegetables, such as oranges, strawberries, and green leafy vegetables. It is not typically found in seafood or seeds in significant amounts.

During sleep, blood pressure typically decreases due to reduced sympathetic nervous system activity and relaxation of the body, which lowers heart rate and vascular resistance.

Diamond is the hardest naturally occurring substance known, with a very high hardness on the Mohs scale, making it harder than copper, iron, or silicon.

Insomnia is a sleep disorder characterized by difficulty falling asleep or staying asleep, which matches option D, 'Inability to sleep.' The other options describe different conditions unrelated to insomnia.

Malleability is the property of metals that allows them to be beaten or rolled into thin sheets without breaking. This distinguishes it from ductility, which refers to the ability to be drawn into wires.

The average distance from the Earth to the Sun is approximately 150 million kilometers, known as an astronomical unit (AU). This is a well-established scientific fact.

Gravity is the force that holds the Earth's atmosphere close to the planet, preventing it from drifting away into space. The other options do not have this effect.

Frozen dew forms when dew freezes on surfaces, which is commonly known as frost. Black ice is a thin, transparent layer of ice on roads, not frozen dew.

Humans typically hear sounds in the frequency range from about 20 Hz to 20,000 Hz. This range represents the normal audible spectrum for most people.