They can put checks and balance on each other.
Answer:
Damand decrease, It has fallen
Explanation:
yes
Gunpowder, the compass,how to make paper and silk. How to make porcelien, and smelting iron and steel.
Two problems sailors faced before the 1400s was they did not have good ways of knowing where they were if they got beyond the sight of land. And 2 the maps were poor and the risk ships were to slow to mak long voyages