1
Q
what is the earths atmosphere today composed of?
A
78% nitrogen
21% oxygen
1% argon
2
Q
what other gas takes up 0.04% of earths atmosphere today?
A
carbon dioxide
3
Q
where is the atmosphere?
A
surrounding earth
4
Q
which 2 gases make up 99% of the earths atmosphere?
A
oxygen and nitrogen
5
Q
when did the earth form
A
4.6 billion years ago
6
Q
what planets are similar to earth billions of years ago
A
mars and venus
7
Q
what did earths early atmosphere contain
A
large amount of carbon dioxide, little to no oxygen, small amounts of other gases such as ammonia and methane
8
Q
how long has earths atmosphere been stable?
A
200 million years
9
Q
when did algae first evolve?
A
2.7 billion years ago
10
Q
what does carbon dioxide do in water?
A
dissolve
science yr 9
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