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Passage 1  Trees are useful to man in three important ways; they provide him with wood and other products; they give him shade; and they help to prevent droughts and floods.  Unfortunately, in many parts of the world, man has not realized that the third o

Passage 1  Trees are useful to man in three important ways; they provide him with wood and other products; they give him shade; and they help to prevent droughts and floods.  Unfortunately, in many pa