Answer:
Ask students to name different forms of carbon that they have encountered. Define key terms such as photosynthesis and respiration. Then ask what role carbon dioxide plays in the atmosphere. This discussion enables you to scaffold or challenge students' learning appropriately later on.
Nitrogen is an essential element, and humans need it to survive. The nitrogen cycle is made up of the processes that move nitrogen between the air, soil, animals, humans and plants. Nitrogen moves from the air to the soil, from the soil to living organisms, and from decomposing living organisms back into the air.