Answer:
Because of product's use of natural resources in its input (1) and dependence on the supply chain system of other companies.
Step-by-step explanation:
The reason is that all of the companies rely on natural resources that the companies are processing and making it available for the other companies to utilize it to control its cost and complete the production of the products. The energy is a natural resource which every company utilizes and due to this its production is largely dependent on the firms that are processing natural resources to make it available for companies to utilize it.
The next most important thing is supply chain system of natural resource companies that helps the companies like AEC and even an individual to make the use of these natural resources in an efficient and effective manner. If I don't have access to fuel, then I cann't travel and traveling by using horses would be expensive and time consuming. So supply chain system of the other businesses play key role here.