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.
Stem cells are characterized by their ability for self-renewal (i.e., maintaining their undifferentiated state during several rounds of cell division), and their potency (i.e., the ability to differentiate into specialized cell types). The two main stem cell types are embryonic stem cells (ES) cells and adult stem cells (i.e., somatic stem cells). Other types, such as induced pluripotent stem cells (iPSCs), are produced in the lab by reprogramming adult cells to express ES characteristics. Embryonic Stem Cells Embryonic Stem Cells Adult Stem Cells Adult Stem Cells Induced Pluripotent Stem Cells Induced Pluripotent Stem Cells.