If there were no nitrogen compounds in the soil, the most immediate effect on plants growing in that soil would be difficulty in synthesizing. . .

Amino acids and Proteins

Explanation:

Plants as well as other living organisms require certain nutrients for their growth and development. One major inorganic nutrient that is needed by plants is NITROGEN, obtained in its compound form called nitrates. Nitrogen is necessary component for building amino acids and proteins in the cell because nitrogen is an integral element in the structure of AMINO ACIDS. Nitrogen makes up the amine functional group of amino acids (NH2).

Hence, If there were no nitrogen compounds in the soil, the most immediate effect on plants growing in that soil would be difficulty in synthesizing AMINO ACIDS and subsequently PROTEINS.

i'm thinking (a) to keep sand in place; ////////////

explanation: a sand fence or sandbreak, like a snow fence, is used to force windblown, drifting sand to accumulate in a desired place. sand fences are employed to control erosion, sand dune stabilization, keep sand off roadways, and to recruit new material in desert areas.

it takes hundreds of years to become stable.

if you have another question lmk.