Answer:
According to John Snow, the cause of cholera was contaminated water
Step-by-step explanation:
By talking to local residents, Snow identified the source of the outbreak as the contaminated public water pump on Broad Street. He did this by mapping the deaths from cholera, and noted that they were mostly people whose nearest access to water was the Broad Street pump. It was later discovered that the water for the pump was polluted by sewage contaminated with cholera from a nearby cesspit.