At the end of this activity, students should be able to: û explain how the Earth's atmosphere evolved before reaching its present composition û describe the approximate percentage composition of the atmosphere at present û discuss the structure of the atmosphere û describe the process of formation of radicals by the break-up of a covalent bond û explain how chlorine radicals can deplete the ozone layer û explain the effect of the ozone-hole expansion on human health û explain how the ozone layer is formed û describe the causes of the greenhouse effect, and what impact it could have on the living conditions on Earth.

Originally released by Learnetic, 2016.