Ozone layer in the atmosphere is very important to life as it cuts off most of the ultra-violet radiations coming from the sun and protects us from their harmful effects. If ozone layer in the atmosphere disappears completely, then all the harmful ultra-violet radiations coming from the sun would reach the earth. These ultra-violet radiations would cause skin cancer in human beings and animals and also damage the plants. All the life on earth would then be gradually destroyed.
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Importance of CO2 (Carbon dioxide):
CO2 gas shows green house effect due to which atmosphere becomes warm. Warm atmosphere is suitable for life on the earth. CO2 gas of atmosphere is also needed by the green plants for making food by the process of photosynthesis.