Every part of our world is made up of tiny building blocks. Carbon is one of these little building blocks. Carbon can be in one thing and then move into another. There is carbon in the air we breathe. It is in the form of carbon dioxide. These building blocks are called atoms. This edition focuses on the oxygen cycle. As students learn about the oxygen cycle and related geography, they’ll move through the scientific method and will read, question, experiment, and record their findings.