The definition of symbiosis has varied among scientists. Some advocated that the term symbiosis should only refer to persistent mutualisms, while others thought it should apply to any type of persistent biological interaction (in other words mutualistic, commensalistic, or parasitic).
The League of Nations failed for a couple of reasons: 1  The United States was not part of it. 2  More importantly, the countries in the League did not take the idea of collective security seriously.3  When countries attacked others, nothing was done. 4  For example, Italy attacked Ethiopia and Japan attacked China. The United States was not part of it. 2  More importantly, the countries in the League did not take the idea of collective security seriously. 3  When countries attacked others, nothing was done. 4  For example, Italy attacked Ethiopia and Japan attacked China. 5  In both cases, nothing serious was done.
League of Nations. International organization founded in 1919 to promote world peace and cooperation but greatly weakened by the refusal of the United States to join. It proved ineffectual in stopping aggression by Italy, Japan, and Germany in the 1930s.