The correct answer for the question that is being presented above is this one: "B. building of the transcontinental railroad --> disappearance of the frontier." The pair of events that did the first event most directly influence the second is the building of the transcontinental railroad --> disappearance of the frontier.
Water, wind, gravity, and ice because they wear away or break up rocks, sediments, and soil from the Earth's surface.
Answer:
2,520
Explanation:
The word ALGEBRA has 7 letters with the letter A repeated twice.
Hence we permute all 7 letters with A repeated twice
₇P₇ / 2! = 7!/ [ (2!) ( 7-7)!]
= 2,520
