The Total World Population in 2012 Is Estimated to Be

Multiple Choice

The total world population in 2012 is estimated to be over 7 billion individuals.The total world population is forecasted to hit 9 billion by 2050, at which point the United Nations predicts the total population will either stabilize or peak after growing for centuries at an ever-accelerating rate.The main reason for this major shift is ________.

A) the unprecedented rate at which world population is aging
B) the decline in birthrates as nations advance economically
C) the high level of mobility of the international workforce across national borders
D) the alarming rate of depletion of natural resources necessary for sustaining the population