Question

what process must happen to gaseous nitrogen before plants can use it to grow?
a. respiration
b. photosynthesis
c. precession
d. fixation

Explanation:

Plants cannot directly use gaseous nitrogen (N₂) in the atmosphere. Nitrogen - fixation is the process by which atmospheric nitrogen is converted into ammonia or other nitrogen - containing compounds that plants can absorb and use for growth. Respiration is the process of releasing energy from food. Photosynthesis is the process by which plants make their food using light energy. Precession is an astronomical or physical phenomenon and not related to plant nitrogen use.

Answer:

D. Fixation