It proves the solution in a real world setting that can be replicated and confirmed by others
Answer:
Airplanes
Explanation:
Commercial and Freight aviation has come a long way. From using out dated B-16 bombers for passengers we are now using beautiful technology like Boeing-747-400, Airbus A-380, and the massive and intimidating freighter AN-225. Imagine the fact that we come from a small 2 passenger glide with one propeller to Fighter Jets that can go more then 400 KM/H all over the world like the American F-18 or the American Stealth B-2 bomber. Commercial aviation also came a long way. Before we used B-16 airplanes that couldn't fly high up which caused turbulence and discomfort. The break thru in aviation was the first ever commercial airliner to break the Altitude of 43,000 feet was the Boeing 747-100.
The U.S gained many people of French heritage.
Chinese troops entered Tiananmen Square on June 4 and fired on civilians.
