In the root nodules of legumes, nitrogen-fixing bacteria form a mutualistic relationship with the plants. Which of the following observations best supports the claim that this
relationship is an example of mutualism?
O The bacteria use nutrients provided by the plant for food, eventually leading to the death of the
plant.
O The bacteria and the plant both require the same limited resources of water and soil to survive.
O The un B bacteria obtain carbohydrates from the plant, and provide nitrogen in a usable form for the
plant.
O The bacteria provide nitrogen in a usable form for the plant, and receive no benefit from the
plant.