A common feature of starch and glycogen is that molecules of both A. are important structural components of plant cell walls B. contain repeated monomers of glucose and galactose C. form microfibrils that give support to connective tissue fibers D. store energy for use by living organisms

D. store energy for use by living organisms

Explanation:

Starch and glycogen are polymers made up of several units of glucose. Starch and glycogen functions to store energy that is used by living organisms.

Starch is a stored form of energy found in plants whereas glycogen is a stored form of energy in animals.

Hence, the correct option is "D".