Where is over 95% of incoming ultraviolet radiation absorbed?
a. the stratosphere
b. the mesosphere
c. the troposphere
d. the thermosphere

The correct answer is a. the stratosphere.

The stratosphere is the second layer of the Earth's atmosphere, and it is the second densest layer as well. In this layer, there's a zone where the dominant gas is the ozone (0³). The ozone is the one that is the most responsible for the absorption of the ultraviolet radiation of the Sun. Unfortunately, this layer is becoming more and more damaged because of the human activities, and urgent measures have to be taken sooner rather than later for its protection.