Earth s mantle is
a. a layer of molten metal.
b. a layer of hot rock.
c. a dense ball of solid metal.
d. a layer of rock that forms earth s outer skin.

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

Answer they are produced by collision of tectonic plates;

Answer after wwii, communist countries in eastern europe formed the warsaw pack, a military alliance, and comecon, an economic alliance;