Here's why it's called that:

* Ribose: The sugar in RNA is called ribose.

* Deoxy: This prefix means "lacking oxygen".

* Deoxyribose: Deoxyribose is a modified form of ribose that lacks an oxygen atom at the 2' carbon position.

The deoxyribose sugar forms the backbone of the DNA molecule, linking to phosphate groups and nitrogenous bases.