One topic looked at in GCSE Science is the changes which have and do occur on the Earth and in its atmosphere. This is the second of three quizzes on the subject and it focusses specifically on the Earth's atmosphere and the gases found there.
Something that you probably take for granted is the atmosphere around us and the gases that we breathe. But the atmosphere doesn't only supply the oxygen that our bodies need for respiration, it also protects us from space. High level ozone protects us from the effects of the most harmful ultra-violet rays from the Sun and carbon dioxide ensures that the Earth's temperature stays within the limits needed for life. The atmosphere also protects us from most fragments of space debris by causing them to burn up well before they hit the Earth's surface and it allows water and carbon to be recycled through food chains.