A plant converts some of the glucose it has just made into an insoluble substance and stores it in the leaf. Which substance is that?

Explanation

Glucose dissolves easily and would upset the water balance of a cell if it built up, so the plant links the sugar units into an insoluble store instead. The other substance built from sugar units gives cell walls their strength rather than acting as a store, protein cannot be made from sugar alone, and the green pigment is not a food store at all.