The diagram shows genetic structures. Which label best represents the area marked Y?

The area marked Y is the DNA.

Explanation:

As we can see in the diagram, The area labelled Y shows a double-stranded structure which is joined together from the centre. The structure of the DNA comprises of two strands which make up the backbone of the DNA. These strands are made up of sugar-phosphate backbones. The strands are joined together by the hydrogen bonding between the nucleotide bases. Hence, the structure Y is that of a DNA.