Final answer:
A common problem in tenement buildings in the early 1900s was poor ventilation due to the lack of windows.
Step-by-step explanation:
In the early 1900s, a common problem in tenement buildings was poor ventilation due to the lack of windows. Tenement buildings were crowded and typically had inadequate windows or no windows at all, which made it difficult for fresh air to enter the building. This lack of ventilation led to stuffiness and the spread of diseases.
Learn more about Tenement buildings in the early 1900s