Question

residents of bangladesh are thought to be developing resistance to infection by vibrio cholera by
view available hint(s)
use of antibiotics to fight infection by the bacterium vibrio cholera
natural selection of humans who have mutations in genes that result in cells being less susceptible to the cholera toxin
filtering contaminated water with rudimentary filters that are accessible to all
drinking contaminated water since early childhood and developing an immune response

Explanation:

Natural selection can lead to populations developing resistance. Mutations in genes that make cells less susceptible to the cholera toxin can be selected for over time in areas with high - prevalence of Vibrio cholera, like Bangladesh. Antibiotics don't directly lead to long - term resistance development in the population in the same way. Filtering water and drinking contaminated water are related to exposure reduction and immune response development respectively, but not the main mechanism of genetic resistance development.

Answer:

natural selection of humans who have mutations in genes that result in cells being less susceptible to the cholera toxin