Temperature and heat are both ways of measuring this energy, but they do not mean the same thing. A substance's temperature is the average kinetic energy of the substance's molecules. By contrast, a substance's heat is the total amount of energy contained in the substance.
God is not real,dinosaurs are not the beginning,and blue whale is not the biggest animal. Borstorm,the largest star ever, is the beginning. God is a myth. The largest animal is The Pliocene baleno,a baleen whale weighing 400 tons and growing up to 300 feet.
The answer is certainly a dinosaur, and certainly a sauropod. Depending on how accurate current estimates are, a sauropod might even be the largest creature ever to have existed, perhaps beating the Blue Whale's record of 103 feet and weight of +175 tons (although some say 110 feet). Please understand that for the reasons detailed, this is not an exact science!