Directions: The diagram below models part of the nitrogen cycle. Use the diagram to answer any questions that follow.

What happens to the nitrogen at W?

a
Its usable form is inhaled and turned into proteins by the rabbit.
b
Its usable form is bonded with other molecules in the atmosphere.
c
Its unusable form is directly transferred up the tree roots.
d
Its unusable form is converted into a form that is usable by bacteria in the soil.

d. Its unusable form is converted into a form that is usable by bacteria in the soil.