What are monosaccharides?

Monosaccharides are recognized as the simplest form of carbohydrates. They are the building blocks of more complex carbohydrates, such as disaccharides and polysaccharides. A monosaccharide consists of a single sugar unit and cannot be hydrolyzed into simpler sugars. Common examples include glucose, fructose, and galactose, which serve as fundamental energy sources for living organisms. Their structure typically includes a carbon backbone, with a corresponding number of hydrogen and oxygen atoms, following the general formula (CH₂O)n, where 'n' is the number of carbon atoms.

The other choices reference different biological macromolecules: complex carbohydrates consist of multiple monosaccharide units linked together, which is not applicable to monosaccharides themselves. Proteins are made up of amino acids, while fatty acids are components of lipids, neither of which relate to monosaccharides directly. This distinction clarifies why identifying monosaccharides as the simplest carbohydrates is accurate and fundamental to understanding carbohydrate biology.