River-valley civilizations developed in Sumer, Egypt, China, and the Indus River Valley. After following the procedures in the Planning a Compare and Contrast Essay worksheet, write an essay comparing and contrasting these civilizations.

Don’t use up to much of them it leads to pollution

So  if  the sum of the enthalpies of the reactants is greater than the products, the  reaction  will be  exothermic.  if  the products side has a larger enthalpy, the  reaction  is  endothermic. you may wonder why  endothermic reactions, which soak up energy or enthalpy from the environment, even happen