More cards in this set

Card 6

Front

What reduced the amount of CO2 in the atmosphere

Back

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Card 7

Front

What was the first evidence of oxygen

Back

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Card 8

Front

Where did oxygen come from after

Back

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Card 9

Front

How much nitrogen is there in today’s atmosphere

Back

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Card 10

Front

How much oxygen is there in today’s atmosphere

Back

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Card 11

Front

How much of other gases are there in today’s atmosphere

Back

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Card 12

Front

What is one practical that can show how much oxygen there is in the atmosphere

Back

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