Answer:
(2) diffusion
Explanation:
Diffusion is a process in which molecules moves from a region of higher concentration to the region of lower concentration. In this condition, plant roots contain high concentration of nitrates than soil so nitrates moves from roots through semi-permeable to the soil by the action of diffusion until the concentration is uniform or equilibrium.
Answer:
Excess nitrogen can cause over-stimulation of growth of aquatic plants and algae. Excessive growth of these organisms, in turn, can clog water intakes, use up dissolved oxygen as they decompose, and block light to deeper waters. So few organisms live in these conditions or even can suffocate and die.