question_answer 26)

  Flow of energy in an ecosystem is always              (a) unidirectional                                                              (b) bidirectional (c) multidirectional                                                          (d) no specific direction,

Answer:

                    (a) Flow of energy in an ecosystem is always unidirectional. This is because the energy that is captured by the autotrophs cannot revert back to the solar input and the energy which passes to herbivores cannot come back to autotrophs. The energy moves progressively through various trophic levels so, it may not be available to previous level.