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killian killian
wrote...
Silver Member
Posts: 6024
10 years ago
From where did the oxygen in the earth's atmosphere originate?
A) photosynthesis from plant life and single-celled organisms
B) chemical reactions between gas in the upper atmosphere and the solar wind
C) outgassing from volcanoes
D) atmospheric bombardment
E) oxidation of surface rocks
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2 Replies
Smiling Face with Open Mouth

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wrote...
10 years ago
Now, I could be wrong but I am sure it is A
killian Author
wrote...
Silver Member
10 years ago
Thanks sir
Smiling Face with Open Mouth
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