Q18. In gel electrophoresis, separated DNA fragments can be visualized with the help of

Solution:
Gel electrophoresis is a technique for separating DNA fragments based on their size and net electric charges.
The DNA fragments separate-out according to their size because of the sieving property of agorose gel. Hence, smaller the fragment size, the farther (faster) it will move.
The separated DNA fragments are visualised after staining the DNA with ethidium bromide followed by exposure to UV radiation.