An element is a pure substance that is made from a single type of atom. Elements are the building blocks for all the rest of the matter in the world. Examples of elements include iron, oxygen, hydrogen, gold, and helium.
Since the initial discovery that the adult brain contains stem cells that generate new neurons, an important question in neurobiology has been whether or not this adult neurogenesis is functionally important.
Stem cells are the cells that have an ability to become various types of cells. Stem cells have unique properties that other cells do not have. First, to understand what stem cells are, you need to understand how humans and other mammals develop: 1. Sperm fertilizes an egg and forms a single cell called a zygote.2.his ability to become any type of cell in the body is called pluripotent. The difference between totipotent and pluripotent cells is only that totipotent cells can give rise to both the placenta and the embryo. 4. As the embryo grows these pluripotent cells develop into specialized, multipotent stem cells.