According to ice core data
A)carbon dioxide concentrations have cycled over the last 800,000 years,but current concentration is higher than anytime over the last 800,000 years.
B)carbon dioxide concentrations today are part of the normal cycling that has occurred over the last 800,000 years.
C)carbon dioxide concentrations today are less than the highest concentration during the last 800,000 years.
D)carbon dioxide concentrations over the last 800,000 years averaged 278 ppm,which is about the same as carbon dioxide concentrations today.
E)carbon dioxide concentrations today are higher than the average over the last 800,000 years,but not higher than the highest concentration measured about 350,000 years ago.

Question

Quizplus · Accepted Answer

Ice core data show that while carbon dioxide concentrations have indeed cycled over the last 800,000 years, the current concentration significantly exceeds any levels found during that period, indicating a break from the natural cycling observed in the past.

According to Ice Core Data