Multiple Choice
What best describes how carbon dioxide concentrations in the atmosphere have changed in the last 500 years?
A) Concentrations were mostly steady until ~1850 when they began to increase.
B) Concentrations increased until ~1850 when they began to decrease.
C) Concentrations decreased until ~1850 when they began to increase.
D) Concentrations varied wildly until ~1850 when they became more constant.
E) Concentrations have remained constant throughout history.
Correct Answer:

Verified
Correct Answer:
Verified
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