After restriction digestion several bands appear in a gel. What do these bands represent?

Correct answer: DNA fragments of different sizes

The governing concept is that restriction enzymes cut DNA at specific recognition sequences, producing fragments of different lengths. During agarose-gel electrophoresis, DNA fragments move toward the positive electrode because DNA carries a negative charge. Smaller fragments pass more easily through the gel network and travel farther, whereas larger fragments remain closer to the wells. Each visible band usually represents many DNA molecules of approximately the same length, not one unrelated substance. Therefore option A is correct. Hormones, fat droplets, and soil particles do not explain the characteristic DNA separation pattern produced after restriction digestion.