Final answer:
The length of PCR products is determined by the length of the primers used in the PCR reaction.
Step-by-step explanation:
The length of the PCR products is determined by the length of the primers used in the PCR reaction. Primers are short DNA sequences that bind to the template DNA during PCR and act as starting points for DNA synthesis. The PCR reaction uses a DNA polymerase enzyme to copy the DNA between the primers, resulting in the amplification of a specific target DNA segment. Therefore, the length of the PCR product is determined by the distance between the primer binding sites on the template DNA.