A) A fort was established and many were killed by diseases
Lewis and Clark's expedition was not positive to the native of Mandan village the most devastating epidemic was the smallpox outbreak in the year 1837 killing a lot of people. The epidemic played an important factor in uniting the surviving Mandans and Hidatsa who later engaged in trade, farming and hunting.
Many were more interested in searching for gold and making new homes.
The policy is known as the "Open Door Policy."
John Hay created this idea in hopes that America and countries all over Europe could trade peacefully with China. This concept was developed in order to protect America's trade interests while also ensuring that no other country would establish a monopoly on trade with China. Within this policy, all countries would agree not to interfere with another country's trade with China.
