Final answer:
Carbohydrates are made up of carbon, hydrogen, and oxygen in a ratio of 1:2:1. They are classified into three subtypes: monosaccharides, disaccharides, and polysaccharides.
Step-by-step explanation:
Carbohydrates can be represented by the stoichiometric formula (CH₂O)n, where n is the number of carbons in the molecule. In other words, the ratio of carbon to hydrogen to oxygen is 1:2:1 in carbohydrate molecules. This formula also explains the origin of the term "carbohydrate": the components are carbon ("carbo") and the components of water (hence, "hydrate"). Carbohydrates are classified into three subtypes: monosaccharides, disaccharides, and polysaccharides.