Dental caries also known as tooth decay is an infection, bacterial in origin that causes destruction of tooth. Fluorine prevents dental caries.
Alternative explanation: Fluoride appears to prevent cavities.
Which chart depicts the evolutionary relationship between the hummingbirds and flowers described?
Certain types of red-colored flowers produce nectar that is chemically ideal as food for a hummingbird. The hummingbird can easily locate these flowers because it can see the color red especially well. The recurved petals of these flowers remain out of the hummingbird’s way while it extracts nectar with its long beak that is perfectly suited for the task. As it does so, the hummingbird’s head feathers brush against the flowers, collecting pollen that it carries away and disperses.