When comparing cholera outbreaks of the past and present, we said that 19th-century London and present-day Zimbabwe have poor healthcare by modern standards. How can we explain the poor healthcare in these situations?

In 19th-century London, people had not yet established that cholera spread through contaminated water, so they did not understand its source. In present-day Zimbabwe, the cause of cholera is known, but limited resources can prevent reliable access to clean water and treatment. Therefore, the correct choice is D: London did not know the source of cholera, and Zimbabwe lacks the resources to treat water.

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