the blanket of gases surrounding Earth, made up of distinct layers that differ in temperature, density, and composition. The layers include the troposphere (lowest level), stratosphere, mesosphere, and thermosphere (highest level).
pltintern
Christine Song supports both Project Learning Tree (PLT) US and Canada's program delivery and reporting, program research, and communications. Christine holds a Master of Environmental Science from the University of Toronto and and a combined degree with a Bachelor of Science in ecology and zoology and a Bachelor of Science in anthropology from the University of Calgary.
