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.
Both nations were eventually admitted to the League, but both left during the 1930s, along with foundation member Japan. Many have pointed to the League's inability to enforce any of its resolutions in the face of aggression and the absence of key nations as primary causes of the Second World War.