Question

which of the following trace elements may be added to bottled water in an effort to prevent tooth decay?
○ nitrogen
○ chlorine
○ fluoride
○ sodium

Explanation:

Fluoride is commonly added to water (including bottled water in some cases) to prevent tooth decay as it helps strengthen tooth enamel. Nitrogen is a major component of air and not added for dental - health purposes. Chlorine is mainly used for disinfection in water treatment, not for preventing tooth decay. Sodium is a common ion in water but not added to prevent tooth decay.

Answer:

C. fluoride