Questions

The medicinal branch of science that deals with the study of skin, hair and nails, their structure, functions and its diseases is called as Dermatology and the person who specializes in that is called as Dermatologist.

On December 21, the earth is in an equivalent position on the opposite points in its orbit, So the South pole is tipped towards the sun and North pole away from it resulting in 24 hours of darkness at the North pole, as the sun is overhead on the Tropic of Capricorn. This phenomenon is winter solstice; while on June 21, North pole is tipped towards the Sun but the South pole is tipped away from the sun resulting in 24 hours of darkness on the South Pole, as the sun is overhead on the Tropic of Cancer.This phenomenon is summer solstice; while Aphelion is the position of the earth in its orbit when it is at its distant point from the sun.

A modem is a hardware device which performs both modulation and demodulation. MODEM means (Modulator-Demodulator).

It is due to the deficiency of Vitamin A. Retinol which is present in vitamin A. Its deficiency causes night blindness. It is available in carrots.