<span>1.The Chinese did not have any more uses for a navy.
2.The voyages were becoming to expensive.
3.They wanted to divert their attention to stopping the Mongolians.
4.The Chinese began to adopt a policy of isolationism and did not want to interact with anyone.</span>https://answers.yahoo.com/question/index?qid=20130423165801AABEmGv
The constitutional convention was in 1787
Group A I believe
Hot-air balloon flights pioneer air travel
Aviators fly gliders—heavier-than-air aircraft with no engines
Development of engine-powered machines with propellers and lightweight motors
First-ever flight across the English Channel
Construction of the first military airplanes
<span>World's first scheduled commercial airline</span>