Final answer:
The vertical division of the atmosphere into troposphere and stratosphere is due to temperature changes with altitude, with the troposphere cooling and the stratosphere warming as a result of ozone absorbing UV radiation.
Step-by-step explanation:
Vertical Division of the Atmosphere
The vertical division of the lower part of the atmosphere into the troposphere and the stratosphere is a result of temperature variations with altitude. The troposphere is the layer closest to Earth's surface and extends up to the tropopause, located at around 12-15 km altitude, where the temperature reaches its minimum. This layer cools with altitude because the warm air, heated by the surface, rises and is replaced by descending currents of cooler air. The stratosphere starts just above the tropopause and extends up to about 31 miles above the Earth's surface, and is characterized by a temperature increase due to the absorption of ultraviolet (UV) radiation by ozone. The transition region between these two layers is marked by the coldest temperatures in the atmosphere and is known as the tropopause.
The different behaviors in temperature are crucial for determining weather and climate. The troposphere is the section of the atmosphere relevant to the greenhouse effect, where weather patterns and clouds are formed through the process of convection. On the other hand, the stratosphere houses the majority of atmospheric ozone, providing protection from harmful UV-B rays, which can cause skin cancer and genetic damage in living organisms.