Where would you most likely find nitrogen-fixing bacteria?

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

Answer: (C)

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, through a process called nitrogen fixation.
2. Recall the natural habitats where nitrogen fixation is most beneficial: Nitrogen-fixing bacteria often form symbiotic relationships with plants that require nitrogen for growth.
3. Identify the specific location where these bacteria commonly reside: They are typically found inside root nodules of leguminous plants, where they live in mutualistic association.
4. Eliminate incorrect options by understanding cell biology and ecology: Mitochondria are organelles inside animal cells and do not host bacteria; saltwater oceans have nitrogen-fixing bacteria but not predominantly; human skin hosts different types of bacteria, not nitrogen-fixing ones.
5. Conclude that the most likely place to find nitrogen-fixing bacteria is inside the root nodules of leguminous plants, where they provide essential nitrogen to the plant.