Answer:
The spark of nationalism in germany and Italy gave their expansionist idea, as they believe they are superior as one race, its nationalism boost the confidence of the nation to wage war with other nations.
These featured include migration of people, invasions, population distribution, and De-urbanization
Under the reign of President Thomas Jefferson, the exploration generally had negative slavery effects on the Americans.
<h3><u>Explanation:</u></h3>
Westward expansion of the US was taken as the key to nation's health by Jefferson. It began early in 1803. He signed a treaty with France in which the US paid a lumpsum amount of money to buy the land near Mississippi river, which infact doubled the size of the country.
Believing that the US needed to expand west to help ensure its survival and prosperity he took this chance to buy the land from Napoleon Bonaparte of France. Though this resulted not in the expansion of the empire rather it became the reason for the destruction of the republic.
<span>This is an example of "The Observer Effect". Researchers will get skewed or inaccurate data if they don't take this "Observer Effect" into account when conducting research or studies.</span>