Here's why:

* Sugars: The backbone of DNA is made up of alternating sugar (deoxyribose) and phosphate molecules. The energy required to *build* the DNA backbone, and therefore the DNA molecule itself, comes from breaking the high-energy bonds within the sugar molecules. This process is facilitated by enzymes during DNA replication.

* Phosphates: Phosphates are essential for the overall process. They:

* Form the backbone of DNA, as mentioned above.

* Provide energy for the process of adding nucleotides to the growing DNA strand. This is done through ATP (adenosine triphosphate), which is a molecule with a high-energy phosphate bond.

* Play a crucial role in activating nucleotides before they can be incorporated into the DNA chain.

Therefore, while sugar and phosphates are essential components of DNA and the replication process, they don't directly provide the *energy* for the process. The energy comes from the breaking of chemical bonds within ATP and other energy-carrying molecules.

Let me know if you'd like to delve deeper into the details of DNA replication!