In the two poems, the journey is a metaphor for life and passage into afterlife. In Ulysses Tennyson talks about how his life is nearing its end and how he's old now while in crossing the bar he talks about dying and going into afterlife. Both poems use the motif of journey on open seas to describe venturing into the unknown, that is, how life passes quickly as a journey does and the next stop on the journey is afterlife.
Nebuchadnezzar is the correct answer
Imperialism is a political and military philosophy in which one country or government seeks to conquer other countries and societies and bring them under the control or influence of the invading country.
Imperialism is often associated with the economic theory of mercantilism, in which the conquering country (known as the metropole) becomes the center of manufacturing and production while the conquered countries (the colonies) become the suppliers of raw natural goods. Under a mercantilist system, the point of having colonies is to enrich the metropole.
Imperialism takes a number of forms. There's settler colonialism, where a metropole established colonies to gather raw goods or resources (New York and Jamestown are examples). There's religious imperialism, in which a country invades other countries for the purposes of spreading a religion (Spain was infamous for this) or establishes religious communities abroad (as in Massachusetts Bay).
Imperialism has also existed for ages and ages. The Romans are one famous example, but virtually every country in Western Europe (France, Britain, Spain, Portugal, Germany, Belgium, etc) had an empire at one point. But so did the Japanese, the Russians, the Zulus, and the Comanches.