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Which gas makes up 21% of the atmosphere?
Which of the following gases makes up the majority of Earth's Atmosphere?
Oxygen at 78%
Nitrogen at 78%
Carbon Dioxide 78%
Which of the following statements are true about oxygen?
it is needed by animals but not by plants
it is needed by plants and animals to release energy from food
it is released by fuels when they burn
it is necessary for fire to burn
Which of the following statements are true about carbon dioxide?
it is essential to life
plants need it in order to produce food
it is used by animals to digest food
it is needed by fuels to burn