The question of whether war is inevitable is one which has concerned many of the world’s great writers. Before   36    this question, it will be useful to introduce some 37 concepts. Conflict,  38   as opposition among  social units-or individuals-directed against one another, is 39 from competition, which    40   opposition among social units 41 seeking to obtain something which is   42   inadequate supply. Competitors may not know about one another, which those who 43 in a conflict do. Conflict and competition are both   44   of opposition. The meaning of opposition has been stated as a process by which social unit function in the disservice of one another, opposition is 45 contrasted to cooperation, a   46   by which social units function in the service of one another. These 47 are necessary because it is important to emphasize that    competition between individuals or groups is inevitable in a world of limited   48  , but conflict isn’t . Conflict, nevertheless, is very likely to occur and is probably an essential and desirable 49 of human societies. Many authors have 50 their arguments that war cannot be avoided on the idea that in the struggle for existence among groups of animals, only those which are best 51 remain alive. In general, however, this struggle in nature is competition, not conflict. Those who fail in this competition 52 starve to death or are 53 by other types of animals. This struggle for 54 is not similar to human war, but is like the competition of 55 for jobs, markets, and materials. The most important quality of this struggle is the competition for the necessities of life that are not enough to satisfy all. 36.A.considering    B.solving C.answering    D.saying 37.A.related    B.used     C.translated    D.sacred 38.A.specified B.remarked     C.defined       D.claimed 39.A.variable  B.distinguished      C.various D.isolated 40.A.acknowledged       B.denies  C.assumes       D.means 41.A.critically B.approximately     C.independently     D.costly 42.A.on   B.for       C.with     D.in 43.A.enter      B.participate   C.fall      D.involve 44.A.formations     B.classes  C.terms   D.reactions 45.A.nevertheless   B.however      C.thus     D.maybe 46.A.procession     B.standard      C.process D.measurement 47.A.accounts B.definitions   C.descriptions D.explanations 48.A.resources       B.origins C.sources D.materials 49.A.matter    B.element       C.event   D.coincidence 50.A.concentrated  B.fixed    C.centered      D.based 51.A.encouraged    B.accepted      C.adapted       D.adopted 52.A.not only B.either   C.neither D.both 53.A.killed     B.raised   C.fired    D.surrounded 54.A.resistence       B.privilege     C.favour  D.employment 55.A.workers  B.officials      C.individuals  D.residents