Contrary to popular perception

(a) the west was the most urban region in america.

(b) most immigrants who settled in the american west did not disturb the environment.

(c) the american frontier experience was unique in world history.

(d) the vast majority of immigrants who settled in the american west were wealthy.

(B) Most immigrants who settled in the American West did not disturb the environment.

Explanation:

It was perceived that immigrants of west disturbed the environment that resulted into more violence and ethnic clashes. But when analysed, it was found that only few immigrants who created such situation of violence but most immigrants adapted to west and did not disturbed environment.  

So the  most immigrants who settled in the American West did not disturb the environment.

answer; i do believe that the answer is (c) electrolyte imbalance or (d) cessation of menstrual cycle; plz check first good luck

answer is b.shrapnel