Of carbon dioxide that was in the atmosphere in prehistoric times. Scientists retrieved this data from air bubbles trapped in ancient ice in Vostok, Antarctica.
Carbon dioxide levels are provided in parts per million (ppm).
400
375
Graph 1: Atmospheric Carbon Dioxide BCE
(www. co2.earth)
350
325
300
Atmospheric Carbon Dioxide Levels
275
250
225
ws
200
175
400,000
300,000
100,000
200.000
Years Before Present
3. What time frame does this graph include?*
1 point
O a. about 400,000 years ago to the present
O b. from the present day to 400,000 years in the future
O c. one million years ago to the present day
O d. the graph does not provide a timeframe