In large crowded cities, where did the poorest residents live?

In the biggest, most crowded cities, the poorest residents (including most immigrants) lived in tenements. A tenement had come to mean an apartment building in the slums— poor, run-down urban neighborhoods. Many immigrants, including women and children, worked in sweatshops in the garment industry.

Explanation:

In the biggest, most crowded cities, the poorest residents (including most immigrants) lived in tenements. A tenement had come to mean an apartment building in the slums— poor, run-down urban neighborhoods. Many immigrants, including women and children, worked in sweatshops in the garment industry.

explanation:

allergens: overstimulate the nerve system

neurotics: attack nerve cells

mutagens: damage or otherwise alter dna sequence

generators: cause defects during growth and development  

carcinogens: cause unchecked cell growth

i hope you get the idea according to me these are the effects that happened.