Explanation:

• The atmosphere consists of different layers with varying density and temperature.
• Density is highest near the surface of the earth and decreases with increasing altitude.
• The column of the atmosphere is divided into five different layers depending upon the temperature condition.
• They are the troposphere, stratosphere, mesosphere, thermosphere and exosphere.
• The troposphere is the lowermost layer of the atmosphere.
• Its average height is 13 km and extends roughly to a height of 8 km near the poles and about 18 km at the equator.
• The thickness of the troposphere is greatest at the equator because heat is transported to great heights by strong convectional currents.
• • This layer contains dust particles and water vapour.
• All changes in climate and weather take place in this layer.
• Hence statement 2 is correct.
• • The temperature in this layer decreases at the rate of 1°C for every 165m of height.
• This is the most important layer for all biological activity.
• o The Lapse Rate is the rate at which temperature changes with height in the Atmosphere.
• Lapse rate nomenclature is inversely related to the change itself: if the lapse rate is positive, the temperature decreases with height; conversely if negative, the temperature increases with height.
• Hence statement 1 is correct.
• • The zone separating the troposphere from the stratosphere is known as the tropopause.
• The air temperature at the tropopause is about minus 80 degrees C over the equator and about minus 45 degrees C over the poles.
• The temperature here is nearly constant, and hence, it is called the tropopause.
• Hence statement 3 is correct.