Question

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What has been the MOST significant cause of the decline in death rate in less developed countries?

The discovery and dissemination of the smallpox vaccine
The beginning of scientific medicine and formal medical colleges
The transfer of disease prevention methods to less developed countries
The development of methods of containing disease-carrying bacteria
The beginning of the single-payer health care system in Western Europe

Answer 1

Answer:

In my opinion, it would be The transfer of disease prevention methods to less developed countries

Explanation:

Why? Because with more PPE and stuff like masks, face shields, vaccines and more, we can help fight many sicknesses and cause a decline in the death rate.

Hope this helps!