If the products of a chemical reaction contain less energy than the reactants, the reaction must...?

Question

If the products of a chemical reaction contain less energy than the reactants, the reaction must...

A) involve the release of energy.

B) result in the production of sugar.

C) be an energy-storing reaction.

D) occur in the cytoplasm of cells.

Answer 1

A) reaction involves the release of energy. Usually this is an exothermic reaction. Heat is given out  

Answer 2

The system has less energy at the end than at the beginning.  Since energy can be neither created nor destroyed, it has to have been released out of the system, usually this happens in the form of light and/or heat.