What are the main conditions necessary for the flow of heat?

What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium. What is their role in N_2 -fixation?

What is imbibition?Which are the various conditions necessary for the imbibition to take place?

What are the main functions of stem?

Give the conditions necessary for seeing an object.

What are the main functions of a leaf?

Name two conditions necessary for rusting of iron.

What climate conditions are necessary for cultivation of jute ?