What are some of the reasons for the large number of migrant workers in mexico?

Who ever answer first get ! question 1 : which pair of words names two processes for treating water to make it clean? a. aeration, precipitation b. coagulation, refurbishing c. filtration, coagulation d. combustion, aeration question 2: which act did the u.s congress pass in 1972 to protect th nation's water? a. anti-pollution act b. watershed protection act c. clean water act d. nixon act