What is the iron law of oligarchy? The

a principle of organizational life under which even a democratic organization will eventually develop into a bureaucracy ruled by a few individuals

Uses good judgement and shows restraint

In  microbiology, pure culture is a laboratory  culture  containing a single  species  of organism. it is usually derived from a mixed culture. pure culture transfers a small sample into new, sterile  growth medium  in order  to distribute the individual cells across the medium surface. it separates the individual cells. when the cells multiply, each will form a colony and it then may  be used to inoculate more medium.