What molecule can serve as an energy source or provide nondigestible materials that increase the amount of roughage in a human diet

There are no options to this question, however, the question can be answered based on general understanding of the topic.

The answer is POLYSACCHARIDE/COMPLEX CARBOHYDRATES

Explanation:

Complex carbohydrates are polymers of simple sugars or simple carbohydrates i.e. they contain a long chain of simple sugars linked by glycosidic bonds. Complex carbohydrates such as starch, cellulose, fiber etc. are contained in the food or diet we consume. Some of these complex carbohydrates such as starch are broken down into glucose, which is used to supply ENERGY to our cells.

However, some other complex carbohydrates such as fiber, cannot be broken down in digestive system and hence provide nondigestible materials that increase the amount of roughage in the human diet.

starchy vegetables are high in carbohydrates.

starchy vegetables contain more carbohydrates than non-starchy vegetables.

explanation:

there are two primary categories of carbohydrates, essentially differentiated on the basis of their carbohydrate content (which is in the form of starch - a complex carbohydrate):

those vegetables which contain little amounts of starch are termed as non-starchy vegetables, and some examples include: artichokes, broccoli and bean sprouts.

vegetables high in their starch content are distinguished as starchy vegetables, and some examples include: potatoes, chickpeas and corn.