Solution: Rhizobium develops nodules on the roots of leguminous plants, according to our findings. Another bacterium, Frankia, produces nitrogen-fixing nodules on the roots of the non-leguminous plant Alnus. So, the following are the answers to the given questions.

a) Yes, the ability of a plant – leguminous or non-leguminous – to fix nitrogen can be purposefully created by genetic engineering.

b) Pine trees and mycorrhiza have a symbiotic interaction. Both creatures profit from each other in this form of connection.

c) To offer mineral nourishment, a microorganism must be in close proximity to a plant.

The rod-shaped Rhizobium, for example, has a close association with various legumes, including sweet pea, lentils, and garden pea.