Correct Option
The correct option is 1 and 3 only.
Explanation
The Earth's atmosphere is a multi-layered envelope of gases held in place by gravity. Its physical properties, such as density and pressure, vary with altitude, and its vertical structure is classified primarily based on temperature gradients.
Statement-wise Analysis
- Statement 1 is Correct: The density of the atmosphere is maximal near the Earth's surface. This is because the gravitational pull of the Earth compresses the gases, concentrating the majority of the atmospheric mass in the lowest levels.
- Statement 2 is Incorrect: Atmospheric density decreases rapidly with increasing altitude. As one moves higher, the column of air pushing down decreases, resulting in thinner air and lower density. It does not increase with altitude.
- Statement 3 is Correct: The column of the atmosphere is vertically divided into five distinct concentric layers based on the temperature condition (temperature changes with height). These layers are the Troposphere, Stratosphere, Mesosphere, Thermosphere, and Exosphere.
Key Takeaway
Key Takeaway: Atmospheric density is inversely related to altitude (highest at the surface), whereas the structural division of the atmosphere into five layers is determined by the vertical temperature profile.