Answer:
Mexicans move in for money.
Explanation:
Many Mexicans leave their native country and move to U.S. for better economic opportunities. There are no better jobs and wages in Mexico. So, people move to towns along US border to earn money fort heir living.It may be temporary stay for some people and some even reside permanently there in U.S. There have been cases where people move to U.S to avoid political and religious issues.
Also, there are towns on the Mexican border which are near American towns because trade between the two countries becomes easier and traders profit.