What effect assembly line and monopoly have on the price of goods

Assembly lines helps with the mass production of a product.
Monopoly of a product is important, because you control the majority of the item on the market.

If you had an assembly line producing say; blankets.  You would be making lots of blankets.  If the majority of blankets on the market are the ones that you made, then you have a Monopoly over them.  
If you know that more supply=less demand, and less supply=more demand, then you know that prices fluctuate.  If you were selling all of the blankets on the market, you could control the price of them to a certain extent, by holding some back, and making a greater demand.
That is Monopoly

The one that most represents the earths mantle would be the skin since the mantle is the upper part of the earths depths which is just like the skin of an apple.