Just by common sense we can rule out both C and B because neither of those make sense for this case. High population really doesn’t matter. So the most logical answer is D. Mostly Defending Familiar Territory

A river valley civilization is an agricultural nation or civilization situated beside and drawing sustenance from a river. A "civilization" means a society with large permanent settlements featuring urban development, social satisfaction, specialization of labor, centralized organization, and written or other formal means of communication. A river gives the inhabitants a reliable source of water for drinking and agriculture. Additional benefits include fishing, fertile soil due to annual flooding, and ease of transportation. The first great civilizations, such as those in Mesopotamia and Ancient Egypt, all grew up in river valleys. Tigris River flourished near Mesopotamia civilization and river nile flourished near civilization of Egypt.
<h2>ꜰᴏʟʟᴏᴡ ᴍᴇ❤</h2>
The correct answer is the 4th option (a more powerful central government that abided by rules).
The first option is incorrect because the government did not give more power to the states.
The second option is incorrect because a monarchy was not formed.
The third option is incorrect because, like the first option, the government did not give more power to the states.
The fifth option is incorrect because the government had an executive branch (the president).
Answer:
A. African slavery
Explanation:
Although we know that slavery was an important part of British Empire it was not a part of their system after 1830s. To be precise in 1833, British Empire prohibited slave trade inside their domain. This was in important change, that rearranged the position of the whole Empire.
Lusitania was an important event in World War I. The death of so many innocent civilians at the hands of the Germans galvanized American support for entering the war, which eventually turned the tide in favor of the Allies. The Lusitania was a British luxury cruise ship.