Which behavior can contribute to the problem of antibiotic resistance?

prescribing antibiotics for serious bacterial infections
patients who do not finish the antibiotics that the doctors prescribe
doctors withholding antibiotics from patients with viral infections
all of the above

Waste water from industries and domestic sources can be treated by chlorination or ultraviolet radiation. there are pros and cons to using either chlorine or uv radiation to kill harmful microorganisms. what is one reason chlorination would be preferred over ultraviolet radiation? a) chlorine only eliminates visible impurities and is ineffective against microorganisms. b) chlorine not only kills bacteria but provides a residual effect on returning microorganisms. c) uv radiation can be used only to treat drinking water and is ineffective in treating waste water. d) ultraviolet radiation is more effective