Where are nitrogen-fixing bacteria typically found?

• A. In saltwater oceans exclusively
• B. In the root nodules of leguminous plants
• C. Inside animal cells
• D. On the surface of leaves

Answer: (B)

Verified step by step guidance

1. Understand the role of nitrogen-fixing bacteria: These bacteria convert atmospheric nitrogen (N\_2) into ammonia (NH\_3), a form usable by plants, which is essential for the nitrogen cycle.
2. Recall the common habitats of nitrogen-fixing bacteria: They are often found in symbiotic relationships with plants, particularly leguminous plants, where they help supply nitrogen to the plant.
3. Identify the specific location in plants where nitrogen fixation occurs: Nitrogen-fixing bacteria typically inhabit specialized structures called root nodules, which are formed on the roots of leguminous plants.
4. Eliminate incorrect options by considering their environments: Nitrogen-fixing bacteria are not exclusive to saltwater oceans, do not live inside animal cells, and are not primarily found on leaf surfaces.
5. Conclude that the typical and most well-known habitat of nitrogen-fixing bacteria is within the root nodules of leguminous plants, where they form a mutualistic relationship.