Why is troposphere the most important of all the layers of the atmosphere?
The troposphere is the most important layer of the atmosphere for two main reasons. First, all changes in climate and weather take place in this layer. This includes phenomena like rainfall, storms, and temperature variations that directly affect life on Earth.
Second, the troposphere is the most important layer for all biological activity. It contains essential components such as dust particles and water vapour that support life processes. Being the lowermost layer of the atmosphere, it is the zone where humans and all living organisms exist and conduct their activities.
Explanation
The textbook explicitly states two key reasons for the importance of the troposphere: (1) 'All changes in climate and weather take place in this layer', and (2) 'This is the most important layer for all biological activity.' Additionally, it mentions that this layer contains dust particles and water vapour, which are essential for weather phenomena and life.