Confidence votes 20.3K. There are two basic types of submarine screws. (Screw is the proper term here as propeller is applied to small craft.) One of the screws is built for silence, and the other is built for speed. Screws built for speed typically have fewer blades and the blades are wider to grab more water as the screw spins in the water.
Economic Definition of assumption. Defined. Term assumption Definition: An initial condition or statement that sets the stage for an analysis by abstracting from the real world. Assumptions are important to economic theories and economic analysis. Some assumptions are used to simplify a complex analysis into more easily manageable parts.
Economic theory defines specialization as the production of one or just a few goods and services. In other words, it refers to how an individual, organization, state or country focuses available resources. Instead of attempting to produce and sell many different products, entities use overstock to trade for what they may lack. The system of international trade uses the concept of specialization. One country may have the resources to produce avocados at a low cost. Another country may choose to specialize in cheese. Each produces more than what they need in order to obtain other goods at a lower cost.