The Black Death most likely traveled by sea when trading ships traveled from Sarai to Paris and other countries throughout Europe.
Galileo confirmed copernicus' theories on the universe with noting that the Earth did indeed revolve around the Sun and not the other way around as was thought at the time. With this he opposed the church dogma at the time.
Equity-efficiency tradeoff results when maximizing the productive efficiency of a market leads to a reduction in its equity—as in how equitably its wealth is distributed.