Final answer:
The most likely consequence of 2.5 billion people suddenly gaining access to toilets and clean water would be a decrease in water-borne disease and diarrhea, leading to improved public health.
Step-by-step explanation:
The most likely consequence of the scenario where the remaining 2.5 billion people suddenly receive access to toilets and clean water is d. There would be a decrease in the amount of water-borne disease and diarrhea, which currently kill many people around the world. Access to sanitation and safe drinking water is crucial for public health. Improved sanitation has proven to decrease the incidence of diarrheal diseases, intestinal worms, and other water-borne illnesses. These diseases are particularly lethal to children under five, a demographic that sees significant mortality rates due to unclean water and poor sanitation conditions.
When people gain access to adequate sanitation facilities and safe water, many of the conditions that create the environment for water-borne illnesses to thrive are mitigated. This leads to improved overall health of the population and can contribute to the prevention of diseases and deaths. As the World Health Organization (WHO) has documented, improving water safety and hygiene could prevent up to 9% of all disease and 6% of all deaths globally, emphasizing the direct link between sanitation and health outcomes.