Short answers, pulled from the story.
A community is a social unit which means it is simply a group of people. This group shares socially significant characteristics that bind them together such as place, norms, culture, religion, values, customs, or identity.
Archaeologists use material culture to identify ancient settlements and social interactions through two meanings for the term community. The first meaning is an informal definition as a place where people used to live synonymous with an ancient settlement like a hamlet, village, town, or city. The second meaning resembles usage in other social sciences where a community is a group of people living near one another who interact socially.
Species interact in three primary ways: competition, predation, and mutualism. Competition typically results in a double negative where both species lose in the interaction while predation involves a win-lose situation with one species winning over the other. Mutualism sees both species co-operating in some way so both win.
Jean-Luc Nancy started this debate with his book The Inoperative Community published in 1991. Maurice Blanchot followed with The Unavowable Community in 1988 and Giorgio Agamben wrote The Coming Community which appeared in 1993.
A seminal study by McMillan and Chavis in 1986 identified four elements of sense of community including membership, influence, reinforcement, and shared emotional connection. Membership means feeling of belonging or sharing a sense of personal relatedness while influence involves mattering and making a difference to a group. Reinforcement covers integration and fulfillment of needs within the collective and shared emotional connection binds these elements together into a cohesive whole.