<span>D. Americans blamed Republicans for the shutdown and Clinton’s approval ratings improved
Hope this helps!</span>
The first one is the correct answer because if the sign if somethings goes from negative to a positive or positive to a negative, everything in the equation switches.
That it led to more free time and that it sparked their creativity to invent stuff, such as fire or the wheel. Domesticating animals led them to a whole new civilization, it gave them surplus amounts of food. That made the civilization thrive with people. Agriculture was a major factor.
Hoped this helped.
~Bob Ross®