BasicStudents matched to this level have a partial mastery of prerequisite knowledge and skills fundamental for proficient work.
At Grade (Proficient)Students matched to this level have demonstrated competency over challenging subject matter, including subject matter knowledge, application of such knowledge to real-world situations, and analytical skills appropriate to subject matter.
AdvancedStudents matched to this level are ready for material that requires superior performance and mastery.
Charles David Keeling began measuring atmospheric carbon dioxide levels on top of Mauna Loa volcano in 1958. These data are extremely valuable in showing how fossil fuel burning is adding carbon to the atmosphere.