(a) What is the primary basis for the division of the atmosphere into different regions? (b) Name the regions of the atmosphere, indicating the altitude interval for each one.

The primary basis for the division of the atmosphere into different regions is the temperature profile and variation of temperature with altitude. As we move upwards, the temperature changes distinctively in different layers, leading to the formation of different regions.

The atmosphere is divided into five main regions, which are as follows: 1. Troposphere: \( \) The troposphere is the layer closest to the Earth's surface. This region extends from the Earth's surface to an altitude of approximately 8 km to 15 km. The exact height varies with latitude and seasons. In this layer, temperature decreases with altitude, and this is where most weather phenomena occur. 2. Stratosphere: \( \) The stratosphere lies above the troposphere, extending from approximately 10 km to 50 km in altitude. In this region, temperature increases with altitude due to the presence of the ozone layer, which absorbs the Sun's ultraviolet radiation, causing this warming effect. 3. Mesosphere: \( \) The mesosphere extends from around 50 km to 85 km in altitude. In this layer, temperature once again decreases with altitude. This is the region where meteors burn upon entry, and it experiences the lowest temperatures found in the atmosphere. 4. Thermosphere: \( \) The thermosphere lies above the mesosphere, with an altitude range from about 85 km to 600 km. Temperature increases with altitude in this region due to the absorption of solar radiation, resulting in extremely high temperatures. The auroras and the International Space Station are found in this layer. 5. Exosphere: \( \) The exosphere is the outermost layer of the atmosphere, extending from around 600 km to the edge of space, which is around 10,000 km. In this region, the air is extremely rarefied, and the boundary between the Earth's atmosphere and outer space is not well-defined.