Here's a breakdown:

* Monosaccharides: These are the simplest forms of carbohydrates, also known as simple sugars. They are the building blocks of complex carbohydrates. Common examples include glucose, fructose, and galactose.

* Disaccharides: These are formed by the joining of two monosaccharides. Examples include sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (glucose + glucose).

* Polysaccharides: These are complex carbohydrates formed by the joining of many monosaccharides. Examples include starch, glycogen, and cellulose.

So, to answer your question directly: Monosaccharides are the monomers that make up complex carbohydrates like polysaccharides.