The following is not a problem that hinders expanded use of coal.

0 votes
     mine safety
      air pollution
      erosion
      land subsidence
      all of the above
      none of the above
asked Jul 2, 2012 in Geography by anonymous
    

1 Answer

0 votes
none of the above
answered Jul 5, 2012 by Geodude ~Top Expert~ (9,680 points)



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