In agarose gel electrophoresis, DNA molecules are separated on the basis of their

1. charge only       
2. size only     
3. charge to size ratio       
4. All of the above


(b) In agarose gel electrophoresis, the DNA fragments separate out (resolve) according to
their size or length because of the sieving property of agarose gel. It means, the
smaller the fragment size, the farther it will move.