Which of the following has been a constant of urban life since the early 1900s? a. decreases in population b. relocation to suburbs c. building and sanitary codes d. increases in industrialization

The Constance of urban life since the early 1900s has been a relocation of suburbs
People who were wealth built second homes in the country to escape sweltering and crowded city during the summer. Many people made it constant to be commuting to the town which was termed as the cheap way and economical. But during the time of railroad, it became expensive due to high rates of fare. 
Suburbanization did not affect all aspects of America because largely functions remained in the cities. For example, courts, goven=rnment bureaus universities, research hospitals, arts, groups, professional sports and theatres.