The central backbone of a glucose molecule is formed by carbon atoms.

Here's why:

* Glucose's structure: Glucose is a six-carbon sugar, meaning it has six carbon atoms arranged in a ring.

* Carbon's bonding: Carbon atoms have the unique ability to form four bonds with other atoms, allowing them to create complex structures like the glucose ring.

* Chain structure: The carbon atoms in glucose are linked together in a chain, forming the backbone of the molecule.

So, while glucose contains other atoms like hydrogen and oxygen, carbon is the key element forming the central structural foundation.