LEARNING TASK 1. A. Fill in the missing words and write your answers in one sheet of paper. 1. Earth is surrounded by a blanket of air called (the atmosphere, oxygen) 2. The atmosphere is a mixture of (gases, rocks) 3. About three fourths of the atmosphere is (oxygen, nitrogen) 4. The layer of atmosphere closest to Earth is the (troposphere, carbon dioxide) 5. Ozone keeps most of the sun's harmful from reaching Earth. (radiation, sound waves)​