Which among the following statements is/are correct about the constituents of the atmosphere?Higher concentration of dust particles is found in the sub tropical and temperate regions.Amount of water vapour decrease with altitudeSelect the correct code from the options given below:

• A. Only 2
• B. Only 1
• C. Neither 1 & 2
• D. Both 1 & 2

Answer: (D)

Dust particles are generally found in the lower layers of the atmosphere. They are found in the form of sand, smoke-soot, oceanic salt, ash, pollen, etc. Higher concentration of dust particles is found in the sub tropical and temperate regions due to dry winds.Water Vapour is formed in the atmosphere due to evaporation from surface water bodies. It is the source of all kinds of precipitation. It acts as a blanket, allowing the earth to neither become too hot or too cold. Amount of water vapour decreases with altitude.