Final answer:
The causes of plagues in cities included filthy conditions, ignorance, and no health laws. Open sewers and poor urban planning contributed to the spread of diseases such as cholera, tuberculosis, typhoid, and typhus.
Step-by-step explanation:
The causes of plagues in cities included filthy conditions, ignorance, and no health laws. Open sewers running through the streets carried human, animal, and industrial waste, which contributed to the spread of diseases such as cholera, tuberculosis, typhoid, and typhus. The poor urban planning, lack of clean water, inadequate sanitation measures, crowded living conditions, and low levels of education also played a role in the prevalence of plagues.