Complex carbohydrates are those that contain three or more monosaccharides linked together. Complex carbohydrates are also called polysaccharides. The polysaccharides in nature are starches, dextrins, and glycogen. Starches and dextrins are really the same thing. Both are of plant origin.
Starches are polysaccharides found in abundance in grains and vegetables.
Dextrins are the starches once they are processed. Glycogen is the stored from of glucose in animals. The chains of glucose molecules clump together to form glycogen. Therefore, glycogen is really just a lot of glucose clumped together in animal tissue ready to provide the body with needed fuel. Fiber is another type of polysaccharide.