Question

in the late 19th century, poor hygiene, greater access to mass public transportation, and growing city populations all contributed to a an economic boom for industrial production. b a basic breakdown of gender roles in america. c greater communication within american society. d a greater likelihood of the spread of disease.

Explanation:

Poor hygiene increases the presence of pathogens. Greater access to mass public transportation and growing city populations mean more people in close - proximity and more movement. Pathogens can spread more easily in such conditions (e.g., through contact in crowded public transport or in densely populated cities).

Answer:

D. a greater likelihood of the spread of disease.