Do some research on what it means to make good backups. For example RAID Is Not A Backup, Simple Copies Are Not Backups, Copies On Same Media Are Not Backups, etc. Agreed. I do use backups on the same Media, however this is something which is annoyingly hard to remedy (in my situation at least). The main issues I have had is when a damp cable tipped a microvolt meter and killed the server, luckily I had a backup (which was an exact clone of the corrupted world files).
Owing to their structural differences, eukaryotic and prokaryotic cells do not divide in the same way. Also, the pattern of cell division that transforms eukaryotic stem cells into gametes (sperm cells in males or egg cells in females), termed meiosis, is different from that of the division of somatic cells in the body.
The most important difference between stem cells and progenitor cells is that stem cells can replicate indefinitely, whereas progenitor cells can divide only a limited number of times.Controversy about the exact definition remains and the concept is still evolving. Bone marrow stromal cells, basal cell of epidermis have 10% of progenitor cell, although they are often classed as stem cells due to their high plasticity and potential for unlimited capacity for self-renewal. 2  Periosteum contains progenitor cells that develop into osteoblasts and chondroblasts.