4 (10 pts) Demonstrate how recursive mergesort works when sorting the following list of numbers: Draw the recursion tree Label each node (i.e., each function call with its parameter) Write the segment of array a that is modified upon each function call's return, e.g., a[1,2)={6,4}. a 1 2 3 4 5 6 7 8 - - - - - - - - - - - - - - - - - - - - - - - - - - | 6 | 1 | 4 | 2 | 3 | 8 | 7 | 5 |