Answer:
Vicksburg was essential to controlling the Mississippi River.
Explanation:
The city of Vicksburg in Mississippi was one of the most important locations that would help determine who succeeds in the Civil War. And it was the desire to conquer this city that Lincoln famously declared as "the key".
Vicksburg was along the Mississippi River and also a major stronghold of the Confederate troops. The capture of this city would determine which way the War will sway. Abraham Lincoln considered it important because it was essential to the controlling of the Mississippi River.
Thus, the correct answer is the third option.
What circumstances conspired to cause the Dust Bowl? Economic depression coupled with extended drought, unusually high temperatures, poor agricultural practices and the resulting wind erosion all contributed to making the Dust Bowl. The seeds of the Dust Bowl may have been sowed during the early 1920s
I believe the correct answer would be the dependence of European nations on loans from the U.S.
Hope it helps!