Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Question: What is used to fluoridate drinking water to promote dental health Answer: calcium fluoride
Calcium fluoride is used to fluoridate drinking water to promote dental health. Crystalline CaF 2 (d = 3.1805 3.

Question: Frequency and intensity are two measurable properties of what? Answer: wave
All waves can be defined in terms of their frequency and intensity.

Question: Because their embryos are surrounded by a thin membrane, reptiles are considered what? Answer: amniotes
Reptiles are also amniotes, which means their embryos are surrounded by a thin membrane.