_____________ fix nitrogen in roots.

The correct answer is: Microbes

• Nitrogen is important for plant growth
• Nitrogen is an important constituent of chlorophyll thereby essential for photosynthesis
• Nitrogen as such cannot be used by plants. Nitrogen is converted into its derivatives like ammonia or nitrates which can be utilized by plants which are called nitrogen fixation.
• In leguminous plants, the roots contain beneficial bacteria called rhizobium which helps in nitrogen fixation
• The rhizobium is present in the form of nodules
• The bacteria convert nitrogen into ammonia which can be used by plants