What helped people of the Neolithic era domesticate plants? clearing the land to raise crops
having more people to work on farms
developing new religions and belief systems
trading with people from nearby settlements

The answer is    d.  central highlands

Well, a and b together would be negative. b alone would also be negative.

Aristotle thought so every portion of the earth tends toward the center until by compression and convergence they form a sphere. travelers going south see southern constellations rise higher above the horizon.~ hope this !