Which of the graphs below best represents the relationship between the levels of carbon dioxide and the average extent of glaciation over the last half million years of Earth's history?
A) Graph A
B) Graph B
C) Graph C
D) Graph D
E) Insufficient information is provided to answer the question.

Question

Which of the graphs below best represents the relationship between the levels of carbon dioxide and the average extent of glaciation over the last half million years of Earth's history? 
A) Graph A 
B) Graph B 
C) Graph C 
D) Graph D 
E) Insufficient information is provided to answer the question.

Quizplus · Accepted Answer

Graph B shows a clear pattern of alternating cycles of glacial advance and retreat over the last half million years, which corresponds well with the known history of Earth's climate. It also shows a correspondence with variations in carbon dioxide levels over the same time period, as indicated by the general trend of the black line. However, the relationship is not a simple or direct one, as some periods of glaciation correspond with relatively high carbon dioxide levels, and vice versa. Nonetheless, Graph B is the closest match to the expected pattern, and therefore the most appropriate choice.

Which of the Graphs Below Best Represents the Relationship Between