The Following Questions Refer to the Graph Below

The following questions refer to the graph below.
Index of Common Stock Prices (1926=100)

-"The periods of World War I [and World War II] coincided with significant migration north from Mexico… [as] many Mexicans moved to the border…[and] easily found work in the United States since domestic mobilization for the war…greatly stimulated business… Although Mexican emigrants did not consider the United States a perfect destination,the economic boom of the 1920s at least presented the possibility of steady employment… However,consequences of the depression in 1929 and 1930 were immediate and unfortunate for the Mexican community living in the United States… The forced repatriations of the Great Depression,very close in time to World War II,painfully showed the Mexican government the truly precarious position of Mexican workers,legal and undocumented alike,in the U.S.economy."
Barbara A.Driscoll,The Tracks North: The Railroad Bracero Program of World War II,1999
Using the excerpt above,answer parts a,b,and c.
a)Briefly explain a cause OR effect of the migration described in the passage during the 1930s using ONE piece of evidence not directly mentioned in the excerpt.
b)Briefly explain a cause OR effect of the migration described in the passage during the 1940s using ONE piece of evidence not directly mentioned in the excerpt.
c)Briefly explain ONE government policy related to the migration described in the passage using ONE piece of evidence not directly mentioned in the excerpt.