The nitrogen in the air cannot be used by producers and consumers. It must be fixed or converted by bacteria in the ground into a useable form for plants called nitrates. Some plants called legumes (beans and clover) actually have bacteria in their roots.
Food is broken down into glucose and then into ATP during cellular respiration. Cells use ATP for energy.
It’s part of the upper mantle just below the lithosphere. Rocks in the asthenosphere are “plastic” meaning they can flow in response to deformation (like silly putty). It’s highly viscous, mechanically weak and ductilely deforming region of the the upper mantle.
