The answer is product (structure).
Explanation:
Escencially, the Product Structure Modeling consits of a hierarchical decomposition of how a product is made, that shapes the companies organization and deparment division. For this case, the two major divisions (Upstream & Downstream) are based on how oil is extracted and refined latter, and then, each subdivsion takes into account how the final product (fuels and lubricants) are made, marketed and sold.
Product Structure Modeling has become a necessity for companies to cope with changes in product configuration.
