General Science Questions

Tyres that are used in an Aircraft for landing are tubeless tyres.

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.

Physical signs of stress include Frequent colds and infections, aches, pains and tense muscles, stomach upset, loss of sexual desire, etc...

The Mercury, planet of the solar system has the highest orbital speed.

Photosynthesis is the process that takes place in leaves that converts light energy into chemical energy or sugars. It occurs in the presence of chlorophyll that is present in leaves as a green pigment, carbondi oxide and water with the help of sun light. So the energy for photosynthesis come from sun light.

Transported soils form from weathered material deposits, which are transported by natural forces to a new site, away from the site of origin.