Question

_ is the active ingredient in most toothpastes.
a. chalk
b. tyradia
c. fluoride
d. gum

Explanation:

Fluoride helps prevent tooth decay by strengthening tooth enamel, which is why it is the active - ingredient in most toothpastes. Chalk is a filler, there is no such common ingredient as Tyradia in toothpaste, and gum is not an active ingredient in toothpaste for oral - health benefits.

Answer:

C. Fluoride