The two functional groups characteristic of sugars are

Step-by-step solution

Monosaccharides can be further classified by their most highly oxidized functional group. Sugars are chemically carbohydrates. They are polyhydroxy aldehydes ketones and their condensation products. Aldoses bear a terminal aldehyde or -CHO group while ketoses have an internal ketone or -CO group. Thus, they possess two functional groups, i.e. carbonyl and hydroxyl.