The causes of loss of biological diversity are:

A.Over hunting is perhaps the most obvious direct cause of extinction in animals, as it has affected several large and well-known species
B.Genetic diversity as represented by genetic differences between discrete populations with wild species, is liable to reduction as result of the same factors affecting species
C.A major, though at present largely unpredictable, change in natural environments is likely to occur within the next century as a result of large-scale changes in global climate and weather patterns
D.All of the above