The shaded regions X and Y indicate changes in the energy level of the system. Which of the following correctly identifies these shaded areas? * 2 points Captionless Image Region X = energy released by the system at the start, Region Y = energy released by the system at the end Region X = energy difference between reactants and products, Region Y = sum of energy of reactants and products Region X = energy required to initiate the reaction, Region Y = energy released by the reaction Region X = energy gained by the surroundings of the system, Region Y = energy lost by the surroundings of the system