A student suggests that Earth's climate is changing, partly because of human activities such as burning fossil fuels (i.e. coal, oil, and natural gas), which pumps carbon dioxide (CO2) into the atmosphere. To support her suggestion, she prepares a graph that shows changes of Earth's average temperature and changes in atmospheric CO2 concentration over the past 150 years. Which contains data?
A. the student's suggestion
B. the graphs
C.fossil fuels
D. the act of burning fossil fuels