Final answer:
The energy necessary for fragment separation during agarose gel electrophoresis is provided by electricity, which creates an electric field causing molecules like DNA to move and separate based on size.
Step-by-step explanation:
The energy to separate fragments during agarose gel electrophoresis is supplied by electricity. Agarose gel electrophoresis is a lab technique used to separate DNA, RNA, or proteins according to their size. An electric field is applied to the gel, and molecules like DNA move due to their net negative charge, from the negative electrode (cathode) to the positive electrode (anode). This movement allows the separation of molecules based on size, as smaller fragments move faster and further than larger ones. Using a DNA-specific dye, the separated fragments can be visualized for analysis.