Final answer:
An implied warranty of merchantability is a legal guarantee that a product will meet certain standards of quality and usability. In the context of international trade, countries can set their own safety standards as per WTO rules, but these must be scientifically based and not discriminatory.
Step-by-step explanation:
A requirement that goods must be fit for their ordinary use, pass without objection in the trade, and meet a fair average quality refers to a implied warranty of merchantability. This legal concept is typically part of commercial law or consumer protection law. The implied warranty of merchantability ensures that products sold are fit for the general purposes they are intended for, are of average or middle-range quality, and are comparable in quality and performance within the trade.
Regarding international trade, countries are allowed by the World Trade Organization (WTO) to set their own consumer safety standards, provided they are based on science and do not discriminate unjustifiably between countries with similar conditions. This means that while the United States can enact laws ensuring all food products or cars meet certain domestic safety standards, such laws must have a scientific foundation and not apply unfairly to imported goods.