I think you just typed the answer in the 2nd paragraph:)
I believe the correct answer from the choices listed above is option C. It is the products that is not requires in a chemical reaction. These are the substances that is being produced from the reactants involved in the system which needs the atomic nuclei and energy.
PCR is a laboratory technique used to make multiple copies of a segment of DNA. PCR is very precise and can be used to amplify, or copy, a specific DNA target from a mixture of DNA molecules.
