the dried excrement of fish-eating sea birds, deposited in rocky coastal regions of South America: contains the urates, oxalates, and phosphates of ammonium and calcium; used as a fertilizer.
In prokaryotes there is only one rather simple type of cell division, which produces two identical daughter cells from one progenitor cell. This is asexual cell division, since it involves no sexual union of different individuals.
Other stem cells don't have as much potential for self-renewal and can't make as many types of cells. The most basic kind of stem cells are the cells that make up an embryo soon after an egg is fertilized. These stem cells divide over and over, eventually making almost all the different cells in the body. Adult stem cells, in contrast, are fully differentiated.. That means they are what they are and do what they do. They can't choose another career. In many organs, however, adult stem cells linger throughout life.