In a thermodynamic study a scientist focuses on the properties of a solution in an apparatus as illustrated. A solution is continuously flowing into the apparatus at the top and out at the bottom, such that the amount of solution in the apparatus is constant with time.
(a) Is the solution in the apparatus a closed system, open system, or isolated system? Explain your choice.
(b) If it is not a closed system, what could be done to make it a closed system?