<span>an explanation of a specific relationship
</span>
Answer:
the answer is the 1st one
Explanation:
Answer:
Nitrogen is the most commonly limiting nutrient in plants. Legumes use nitrogen fixing bacteria, specifically symbiotic rhizobia bacteria, within their root nodules to counter the limitation. Rhizobia bacteria convert nitrogen gas (N2) to ammonia (NH3) in a process called nitrogen fixation.