Carbohydrates (carbon and water) are made of C, H, and O,
and are the main source of energy for life.
Like water, these molecules are polar and are "hydrophilic" (water-loving).
The simplest carbohydrates (simple sugars) are monosaccharides.
Larger carbohydrates (complex sugars) are polysaccharides linked by glucose subunits.
In addition to starch, polysaccharides include cellulose and glycogen.
Glucose is the building block of most carbohydrates.