Bacteria found in root nodules of legumes are

Which of the following is a symbiotic microorganism?

What is the function of leghemoglobin?

We find that $Rhizobium$ forms nodules on the roots of leguminous plants. Also,$Frankia$,another microbe,forms nitrogen-fixing nodules on the roots of the non-leguminous plant $Alnus$. Is it necessary for a microbe to be in close association with a plant to provide mineral nutrition? Explain with the help of one example.

Legume plants are important because they

Root nodules for nitrogen fixation in non-leguminous trees are produced by species of the genus