48. According to the passage, which of the following is NOT true? (A)The vague understanding of natural cycles and interactions results in the uncertainty of warming effect. (B) The role of particles in effecting the atmosphere remains debatable in that they can raise as well as lower the temperature. (C) The controversial estimations of temperature trends may result from warming effects generated by artificial development. (D) The role of soot in melting glaciers proves the irrelevance of global warming to glacial receding.