1) Acts 2) Goes 3) Roles 4) Uses 1) The uses of something 2) Uses 
The special activity or purpose structures serve in the political process; for example interest groups to articulate interests.
Pre-programmed formulae provided as part of a spreadsheet or database application.
Three mode PID controller. A time proportioning controller with integral and derivative functions. The integral function automatically adjusts the system temperature to the set point temperature to eliminate droop due to the time proportioning function.