If the value of the gift exceeds $100, you will be required to pay duty. If you have goods you intend to sell in the U.S., they will most likely be subject to duty, unless they are eligible for duty-free treatment under an international trade agreement (GSP, NAFTA, etc.).
Specialization of labor is a powerful force in an economy, benefiting small and large businesses alike. Workers produce more when they occupy specialized roles, so businesses can offer higher quality products at lower prices.
Specialization can also refer to production, for example when in a factory an assembly line is organized in a specialized manner rather than producing the entire product at one production station.