Answer:
Primer 2
Explanation:
The lanes on the gel are all smeared and there is no distinct band. This indicates that many DNA segments, all of different sizes, were created in the PCR process. If at least one primer is within an STR region, the primer can bind to more than one position along the region, resulting in segments of variable lengths. Of the four sets of primers shown, only the primers in image 2 are inside the STR region.
