Phlegm originates from the lungs. It is different from the mucus that is produced in the nasal passages. A common cause of phlegm is post nasal drip which is a symptom of sinus infections, colds, flu and inhalation of irritants. The diagnosis of the underlying condition could be made from the color of the phlegm.
A flow chart is a type of diagram representing a process using different symbols containing information about steps or a sequence of events. Each of these symbols is linked with arrows to illustrate the flow direction of the process.
Another good use is to illustrate the steps of an algorithm (a sequence of instructions used for performing a task). For instance, a computer programmer may create a flowchart that illustrates the steps of a computer algorithm. There are several variations of flowcharts in use today.