A student sets up the investigation shown below. The movement of colored water through the gravel best models — *

The study of where things are 

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 eruptionsseismic waves from earthquakes;

Joe ran 130 yards because 3 feet make 1 yard so using this ratio 390 feet make 130 yards.