Final answer:
Gel electrophoresis is a technique used to separate DNA fragments based on size. Agarose gel is used as the medium, and DNA is loaded onto the gel and driven towards the positive electrode by an electric current.
Step-by-step explanation:
Gel electrophoresis is a technique used to separate DNA fragments of different sizes. Usually, the gel is made of agarose, which is poured into a casting tray and solidified. DNA is then loaded onto the gel and an electric current is applied. The negatively charged DNA molecules move towards the positive electrode, and the smaller fragments migrate faster than the larger ones, resulting in the separation of the fragments based on size.