Scar tissue is made of collagen fibers, just like the rest of your skin. The main difference lies in how these fibers are arranged. Scar tissue has a look and feel that is thicker than the rest of your skin because the collagen is produced as a disorderly mass of fibers.
A pre-order is an order placed for an item which has not yet been released. The idea for pre-orders came when people found it hard to get popular items in stores due to their popularity. Companies then had the idea to allow customers to reserve their own personal copy, before the release, which has been a huge success.
a person appointed to superintend or preside. 2. an administrative officer in any of various colleges and universities who holds high rank and is concerned with the curriculum, faculty appointments, etc. 3. Ecclesiastical. the chief dignitary of a cathedral or collegiate church.