1.) Animals get the nitrogen they need by eating plants or other animals that contain nitrogen.
2.) nitrogen is “unavailable” to plants, because the gaseous form cannot be used directly by plants without undergoing a transformation. To be used by plants, the N2 must be transformed through a process called nitrogen fixation.
3.) Bacteria help the nitrogen change between states so it can be used. When nitrogen is absorbed by the soil, different bacteria help it to change states so it can be absorbed by plants. Animals then get their nitrogen from the plants.
