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Keywords: earth ecology, carbon dioxide, pollution, green house effect, disaster, , online teaching
1. What is the Earth%27s average temperature?
A) about 5 °C
B) about -3 °C
C) about 15 °C
D) about 23 °C
2. The greenhouse effect is the same thing as global warming.
3. Air consists mainly of:
C) carbon dioxide
4. How much carbon dioxide is in Earth’s atmosphere today?
A) 20%25 or greater
B) 10%25 to 20%25
C) 1%25 to 10%25
D) less than 1%25