Page 38 - Science Tour 3
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Gases in the atmosphere
The gases in the atmosphere are nitrogen, oxygen, carbon dioxide
and other gases.
Almost 78% of the atmosphere is nitrogen, 21% is oxygen and 1% is
the rest of the gases combined.
The importance of nitrogen (N2)
Nitrogen is the most abundant gas. It helps living things make
protein and it prevents the Earth from burning.
The importance of oxygen (O2)
The main importance of oxygen is respiration. It is one of the
most essential requirements of life.
The importance of carbon dioxide (CO2)
It helps to keep the
temperature on
Earth suitable for life.
Plants need carbon
dioxide for
photosynthesis.
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