Classify the next examples as laws or theories, considering the definition of each one.
a) When the temperature rises, will be simpler to dissolve a solid into the water.
b) The global warming is due to the excessive emissions of carbon dioxide, and other gases, to the atmosphere and it is the cause of many changes in the climates of the Earth.
c) In a chemical reaction, the total mass of the initial substances is equal to the total mass of the final substances.
d) A chemical reaction implies that substances change their composition and they have to be converted from one to other different substances by the combination of their atoms.