How did the receding ice age with the development of agrarian societies?

I believe the answer is: it allowed for more water to form (from the melting ice) which was used to irrigate and thus grow crops.

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When this happen, people on that period could afford to opened up a lot of agricultural fields even if the fields located pretty far away from water sources. This make agricultural activities able to thrive, which lead to the development of agrarian societies.

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 % " .