4. Nitrogen fixing bacteria are associated with what plants?
Legumes, the plants related to beans and peas. They have in common a bean like fruit called a "legume". The roots of these plants are parasitized by tiny bacteria which are nitrogen fixers, which means they can absorb Nitrogen gas and release a form of nitrogen called nitrates. Note the tiny spherical tubers, these are infested with nitrogen fixing bacteria. These secreted nitrates are an important fertilizer for plants.