Answer:
Biotic community
Explanation:
Definition of biotic :living organisms in the ecosystem .Example Frog,fish,and etc.
Definition of Abiotic: Nonliving things in the ecosystem. Examples wind,water,and etc.
Answer and Explanation: So the plant/algae take nitrogen from the topsoil by captivating through roots, such as the Glutaminic Acids, ammonium ions, or nitrate ions. Plants can't necessarily get nitrogen from instant air, however, plants obtain nitrogen through a natural process.
Hope this helps! :-)
It is A. Those are all decomposers, the other answers like C are all animals. Decomposers are are biotic organisms that break down basically dead plants or animals.