Final answer:
The statement that fluoride absorption is about 20% is false; fluoride absorption rates can be significant and vary depending on several factors.
Step-by-step explanation:
The statement that fluoride is poorly absorbed, with only ~20% transported across the intestine, is False. Fluoride absorption can vary, but a significant amount is usually absorbed by the body. The exact percentage can differ based on various factors, such as dietary components and the chemical form of the fluoride. It is known that water fluoridation is a public health measure to help prevent tooth decay, and as mentioned in the reference provided, fluoride is widely available in community water systems in the United States to support dental health.