Population is undeniably important—but how, for whom, and with what consequences is a complex story. Two things are certain:
<span>Population issues in the 21st century are different from those in the last century. <span> With the development world midway through an uncertain effort to reach the Millennium Development Goals by 2015, population issues will be central to the success or failure of six of the eight goals.</span></span>
Of these options, the only one that was truly true of both the first and second industrial revolution is the "use of the assembly line" although the length of these lines varied.