<span>The answer is: molecule; carbohydrate. A six-carbon sugar is an example of a molecule that can join with other molecules to form a carbohydrate such as starch or cellulose. The basic unit of carbohydrate is monosaccharide. A six carbon sugar would be an example of a monosaccharide. And it can join with other simple sugars (monosaccharides) to form polysaccharides, such as starch or cellulose.</span>
<span>Cytosis requires energy, and the production of energy depends on oxygen. Diffusion does not require energy.</span>