The principle of comparative advantage indicates that trade is a zero-sum activity. a nation can gain by specializing in the production of the goods it can produce at a low opportunity cost and trade for goods it can produce only at a high cost. comparative advantage applies to nations and not individuals.

Which of the following is true about presentation methods for providing training? audiovisual techniques are most effective when they are used alone. mobile technologies include training methods such as on-the-job training, simulations, business games and case studies, behavior modeling, interactive video, and web-based training that require the trainee to be actively involved in learning. the typical users for teleconferencing include employees who are part of a workforce that spends most of its time traveling, visiting customers or various company locations and has limited time available to spend in traditional training activities. webcasting involves classroom instructions that are provided online through live broadcasts. classroom instruction is no longer a popular training method because of new technologies such as interactive video and computer-assisted instruction.