【正确答案】It is not difficult to imagine a world without challenges. It would probably be a kinder world: without demands, without conflicts, without disappointments. Competition would never enter in. Conflict would be eliminated and tension would become a thing of the past. The stress of creation would be at an end. Life span would be extended, for fewer people would die of heart attack or stroke caused by tumultuous endeavor. The stress of competition would be departed from the human heart for good. Ah, what kind of life would it be? An unrelieved boring life. Arnold Toynbee has said that all progress, all development come from challenges and consequent responses. Without challenges there is no response, no development, no freedom.