SME
Grade 12 Science · Problem type
How oxygen filled the air
Use this for “How did the first photosynthesis change Earth’s air, and what did it leave in the rocks?”
Put in order
Put the changes to Earth’s early air and oceans in order.
1
?
2
?
3
?
4
?
5
?
6
?
Assumptions
•
Oxygen first reacted with iron; only after the iron was used up did it build up in the air.
•
Red beds need oxygen in the air, so they date its rise.
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Earth's history: the early Earth, its atmosphere and the history of life
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Early Earth’s air and today’s
Use this for “How was Earth’s early atmosphere different from today’s, and what changed it?”
The history of life
Use this for “Put the major steps in the history of life in order, from the first cells to humans.”