Answer:
The curve that most closely describes the mean tempretire of the fluid as a function of position along the tube.
Explanation:
Hello. Your question is presenting very confusing words, however, through the context of the question as a whole, it is possible to see that you are saying that the water that enters a circular tube has a lower temperature than the temperature presented by the surface of the tube . In this case, if you are going to present a graph about this, it is important that this graph presents a curve that shows the relationship between the average water temperature as a function of the position of the water along the tube. This graph will be similar to the graph shown in the attached figure below.