Why does an organ system need multiple cell and tissues to function?

Cells make up tissues, tissues make up organs, and organs make up organ systems. For instance, digestive system organs cooperate to process food. The survival of the organism depends on the integrated activity of all the organ systems, often coordinated by the endocrine and nervous systems.

answer///(c) the maximum number of organisms an environment can support for a long time; i believe this is correct, plz check luck;