Answer:
Ohio's population tripled between 1820 and 1840 but only increased by about 50 percent from 1840 to 1860.
Although Ohio had ports of entry on Lake Erie, no passenger lists for ships are available. The majority of the immigrants arrived through eastern ports (New York, Boston, Philadelphia, Baltimore) and New Orleans. The library has records for each of these ports from 1820 to about 1920 or later. Philadelphia records start in 1800. Records of persons coming from Canada to the United States were not recorded until 1895. For records after 1895, see "Canadian Border Crossings, 1895-1954" in the the United States Emigration and Immigration.
Explanation:
To work on their plantations, which were their main source of income. The plantations required a lot of really intensive and dangerous work that the colonists did not want to do themselves. They realized that African slaves provided cheap labor and could be easily replaced.
Eventually, the colonists just became over reliant on this slave labor, which is why they “needed” it.
Answer:
The US started sending out destroyer ships and aerial hunter-killer PBY's, Consolidated PBY Catalina. A type of amphibious aircraft. They were essentially flying boats, used as patrol aircrafts. The big advantage of these PBYs were that they could refuel on fueling ships out on the ocean-- they did not need to return to land to refuel, so they were essentially constant. The US had naval and aerial patrols that were 24/7 that could accompany liberty ship convoys. There were up to 10 liberty ships per convoy-- they brought all the needed supplies to the British Isles.
Sophisticated sonar equipment for first detecting, then classifying, locating, and tracking the target submarine is a key element of ASW (Anti Submarine Warfare). To destroy submarines, both torpedoes and naval mines are used, launched from air, surface, and underwater platforms. ASW also involves protecting friendly ships.
As soon the US destroyers detected submarines with their sonar, they would alert PBY's. Once alerted of the location, they would release depth-charges, a big 55-gallon drum, full of explosives, that has pressure triggers. Once the depth-charge reached the depth it was set at to explode, it would detonate and destroy the submarines. They would wait for the enemy U-Boat to surface, knowing they'd hit the target.
Since these patrols were constant, the German U-Boats never stood a chance.
Despite looking at Hitler with suspicious eyes, the French and British officials didn't do anything when Germany annexed part of the Czech land. Instead, the French and the British thought that that would satisfy Hitler's appetites and that he will not dare to make anymore troubles.
They were wrong though. Hitler ordered an invasion of the neighboring Poland, though he was saying that it was not an invasion but it was a defensive action because of the Polish threat toward his country. The Polish though didn't had any ambitions toward Germany, neither they did something to them, nor did they had the military power for such an action. Also, Hitler saw Poland as a place for living of the Germans, and he wanted to exterminate the Polish people.
That triggered the alarm and France and Great Britain declared war on Germany because of its actions and breaking of the treaty, thus the World War II was officially initiated.
