Which factor most contributed to the urbanization of the United States during the first half of the 1900s?
o improvements in trade relation with nations overseas
o mechanization of agriculture
availability of low cost housing in cities
Success of the labor movement

d) the constitution rights of native americans and their right to self-government on reservations

answer: your option is d

explanation:

the causes of the dust bowls were severe droughts,   lands became dry and hard, temperature was higher than usual, hot and dry conditions killed crops, high winds. because of those factors, the winds kicked up dry soil and created clouds of dust.