1. Load the file "isabel/data/isabel.vti".
2. Apply persistent simplification to the field "sf" with a persistence threshold of 0.04
3. Compute the merge tree of the simplified field.
4. Save the nodes of the merge tree as "isabel/results/{agent_mode}/isabel_nodes.vtk" in legacy VTK format. 
This file should have two point arrays. One should be called "CriticalType" and should store the type of critical point for each node. 
It should follow the following convention: 0: minima. 1: 1-saddles. 2: 2-saddles. 3: maxima. 4: degenerate critical points. 
The other point array should be called "Scalar" and should contain the scalar field value at each point in the merge tree.
5. Save the edges of the merge tree as "isabel/results/{agent_mode}/isabel_edges.vtk" in legacy VTK format. 
The file should store each edge as a separate cell with type vtkLine.
6. Analyze the visualization and answer the following questions:
Q1: The parent node of the leaf (377, 265, 0) has coordinates (x,y,z). What is x+y+z?
(A) 627 (B) 854 (C) 992 (D) 1039

Q2: How many edges are there in the merge tree?
(A) 154 (B) 195 (C) 204 (D) 254

Q3: What is the highest scalar field value of a minimum, rounded to the nearest whole number?
(A) 12 (B) 26 (C) 31 (D) 58
Save the answers to the analysis questions in plain text as "isabel/results/{agent_mode}/answers.txt".