Its organism because it is one single thing.
The difference between Food Chain and Food Web is that in ecology, a food chain depicts the continuous flow of essential micronutrients from one level of the hierarchy to the next. A food web is a collection of food chains that are linked at various trophic levels. Food web is an important conceptual tool for illustrating the feeding relationships among species within a community, revealing species interactions and community structure, and understanding the dynamics of energy transfer in an ecosystem.
Acetylcholine helps _initiate_ muscle contraction in the peripheral nervous system (pns), whereas it acts to _inhibit_ muscle contraction in the central nervous system (cns).
