Answer:
it condenses the DNA so that it can fit inside the cell.
Explanation:
Supercoiling is a level of genome packaging and is important for the packaging of the DNA which is about 2m in length inside a nucleus that is about 6microm. Supercoiling refers to the over (positive supercoiling) or under winding (negative supercoiling) of a DNA strand, and is an expression of the strain on that strand. Supercoiling is in compacting DNA, and also allows for the regulation of access of transcriptional machinery and other biological activities to the DNA and in turn gene expression. Certain enzymes such as topoisomerases are able to change DNA topology to facilitate access of DNA replication or transcription.