Some metropolitan areas contain metropolitan divisions. Two metropolitan divisions exist within the DallasâFort WorthâArlington MSA. The term metropolitan division is used to refer to a county or group of counties within a metropolitan area that has a population core of at least 2.5 million.
The bees carry the propolis back to their hives and mix it with their salivary secretions and wax flakes. Propolis contains 55% resins and balsams, 30% beeswax, 10% etheric oils, and 5% pollen.
The beeswax dates to about 35,000 years ago, making it the oldest known example of beeswax being used as a tool. Finally, researchers dated a thin wooden stick scarred with perpendicular scratches. A chemical analysis revealed traces of ricinoleic acid, a natural poison found in castor beans.