question_answer 22)

  The extinction of passenger pigeon was due to (a) Increased number of predatory birds              (b) Over exploitation by humans (c) Non-availability of the food                                  (d) Bird flu virus infection

Answer:

                  (b) Extinction of passenger pigeon (Ectopistesmigratorius) was due to over exploitation by human beings. Factors like increase in number of predatory birds, non-availability of food and bird flu virus infection did not contribute to the extinction of passenger pigeon.