Land affected or burdened by an easement is called a servient estate, while the land or person benefited by the easement is known as the dominant estate.. If the easement benefits a particular piece of land, it is said to be appurtenant to the land.
Vitamin D obtained from sun exposure, food, and supplements is biologically inert and must undergo two hydroxylations in the body for activation. The first occurs in the liver and converts vitamin D to 25-hydroxyvitamin D [25(OH)D], also known as calcidiol.
Vitamin D is the name given to a group of fat-soluble prohormones (substances that usually have little hormonal activity by themselves but that the body can turn into hormones). Vitamin D helps the body use calcium and phosphorus to make strong bones and teeth. Skin exposed to sunshine can make vitamin D, and vitamin D can also be obtained from certain foods. Vitamin D deficiency can cause a weakening of the bones that is called rickets in children and osteomalacia in adults. Two major forms of vitamin D that are important to humans are vitamin D2, or ergocalciferol, and vitamin D3, or cholecalciferol.