Final answer:
A carbohydrate monomer is a monosaccharide, which is classified based on the number of carbon atoms in the molecule. The most common hexose monosaccharide is glucose, while pentose monosaccharides are found in DNA and RNA.
Step-by-step explanation:
A carbohydrate monomer is commonly referred to as a monosaccharide. Monosaccharides are the building blocks of carbohydrates and are classified based on the number of carbon atoms in the molecule. Hexose monosaccharides, which contain six carbon atoms, are the most common, with glucose being the most abundant in nature. Other hexose monosaccharides include fructose and galactose. Pentose monosaccharides, with five carbon atoms, are also important and are found in DNA and RNA.