In a regulated system which of the following must be true In
     In a regulated system, which of the following must be true?  Influx and efflux must be unvarying.  Influx and efflux must be matched on average.  The system must be a closed one.  If influx increases, then efflux must decrease. 
  
  Solution
The correct answer is : Influx and efflux must be matched on average.
Reason: A regulatory system in order to maintain homeostatis has to maintain the process of influx and efflux must be matched on an average.

