Final answer:
Fluoride deficiency can lead to tooth decay and weak bones due to its role in forming fluorapatite, which strengthens bone and tooth enamel, and in preventing cavities.
Step-by-step explanation:
The mineral that is lacking and can cause tooth decay and weak bones is fluoride. This mineral is essential for maintaining bone and dental health. Fluoride helps to stabilize and strengthen bone mineral by forming fluorapatite, which replaces hydroxyl groups in bone's hydroxyapatite crystals. This process also increases the crystals' density. Furthermore, fluoride is crucial for protecting teeth from decay by helping rebuild and strengthen the tooth's enamel, thus preventing and even reversing the formation of cavities.
Insufficient fluoride can lead to a higher risk of dental cavities as well as potentially contributing to the development of weak bones. It is important for proper bone and dental health to include an adequate amount of fluoride in one's diet or through water fluoridation, which is a common public health measure to ensure frequent and consistent contact with low levels of fluoride.