The first ancestors of humans showed up about years ago O A. 4.5 billion O B. 65 million O C. 10,000 O D. 1 million SUBMIT

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 volcanic outgassing;