Political - British taking over Northern Ireland.
The majority of Northern Ireland's population were unionists, who wanted to remain within the United Kingdom. (The Norman invasion of the late 12th century )
Economic - Failure of potato crop. (The Great Famine)
Religious - discrimination against the Catholic/nationalist minority by the Protestant/unionist government and police force.
Answer : Mainly because economic problems. Since potatoes were no longer available in Ireland, the Irish would starve to death since potatoes were their main resource as food.
This brings to Irish migration to the US because it offered low paying jobs for immigrants. In the end, the Irish had minimum money and enough food for themselves in America, unlike in Ireland.
China, Persia, and Russia
The two major outcomes were Germany, together with its allies, was forced to assume the whole responsibility for all the losses and all the damage caused.
By laws of the U.S. Constitution, the federal government is required to carry on a census <u>every 10 years</u> that calculates how many people are currently living in each state. Occasionally, as the population goes up or down in certain states, a <u>reapportionment of U.S. House seats must be done in order to adjust to the changes.</u>
<u>Re-election rates</u> for incumbent members of the congress has always been extremely high. <u>Historically, it has rarely gone down 90%</u>. However, for States that experience slow growth or rapid loss of population, the threat of losing seats becomes an actual concern for congress members.
Hope this helps!