Glucose, galactose and fructose share one chemical formula but differ in structure. What are they called?

1. All three sugars are hexoses and carry the same chemical formula. 2. They still differ structurally and chemically, because the functional groups sit differently around the asymmetric carbon. 3. Molecules with one formula and different arrangements of atoms are isomers. 4. They are not polymers of one another, since each is a single sugar unit. 5. Anomer refers to the two ring forms of one sugar at carbon 1, which is a narrower idea than the difference between glucose and fructose. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 3 "Biological Macromolecules", section 3.2 Carbohydrates_