The answer is the first one because it doesn't create gases and, the third one doesn't even make any sense so its definitely not that one
Switch the first two, so the order will be
Nitrogen Molecules are split apart
Gaseous nitrogen is released.
Dead Animals Decompose
Nitrogen moves from soil to plant material.
The answer is A, water enters threw the roots not the leaves
First box is AA. Second box is Aa. Third box is aa.