How did new machinery make dry farming easier for farmers?

It allowed farmers on the prarie to cultivate crops and plants even though the prarie got very small amounts of rain annually

the han greatly expands the chinese empire. the han dynasty retains the centralized bureaucracy and unified political system of the qin but adopts and grafts upon this the confucian view that government should be run by educated, ethical men.

explanation:

the correct answer is:   "   3.6 % " .

          →   the unemployment rate is:   " 3.6 % " .

explanation:

to calculate the "unemployment rate" :

the "unemployment rate"   =

  [# of people unemployed] /   [working age population]   * 100 %   ;

                =   [9 million] / [250 million]     *   100 % ;

    →     note:   the units of "million" cancel out;

                    since:   " {million} / {million} = 1 " ;

                =   (9 / 250)   * 100 %   ;

                = 0.036 * 100 % ;

                =   3.6 %

answer:   the unemployment rate is:   " 3.6 % " .