When the production, transportation, and the sale of a product are controlled by one company...

Then, that one company has full control of the supply chain management of the product.

Explanation:

The supply chain management is the management of the flow of a good from raw material, to work-in-process inventory, to finished good. It makes sure that goods are transformed, and delivered to the final customer.

When a company controls the production (the making of the product from raw materials), the transportation (the delivery of the finished product to the store),  and the sale of the product (the product is finally delivered to the final customer), then, the company has full control over its supply chain, which can represent a great competitive advantage in the market.

these conditions long with a short growing season made farming difficult.

explanation:

the north has a climate of warm summers and snowy cold winters. the terrain is rocky, hilly, and not good for farming.

well that depends on how deep the hole is. you'd first go through te crust of the earth, then the upper mantle, then the lower mantle then the outer core, then the inner cor then you'd be stuck in the core to melt.