Question

Which part of a plant serves as a home for nitrogen-fixing bacteria?

Answer 1

Mainly the root nodules serve as a home for nitrogen fixation.

Explanation:

Symbiotic nitrogen-fixing prokaryotes have nodules,
the special organs of the plant. These organs are existing as stem glands that develop independently of the symbiont. In the case of legumes and actinorhizal plants, the nitrogen-fixing bacteria induce the plant to form root nodules.

Initially the establishment of the symbiotic relationship
between the nitrogen-fixing bacteria and their host
is the migration of the bacteria toward the roots of the host
plant. This migration is a chemotactic response mediated
by chemical attractants, such as flavonoids and
betaines, secreted by the roots which govern nod genes transcription that helps in the nodule formation.