Which molecules link together to form starch

Glucose

Polymers of Glucose are what we commonly call starch.

Glycogen is also made by linking together glucose molecules. Like starch, it is used by animals to store sugar and provide energy. It is similar to amylopectin in structure, but branched with a C1-to-C6 glycosidic bond about every ten glucose units.

Its either a) or b),wind and water erosion gradually widen the canyon