I am confused about this problem. what does "one with lower indexed" and "one with higher indexed" mean?

Does anyone want to explain for me? Thanks, more details are better.

D Question 1 1 pts You are running mergesort on an array with the contents: 1, 8, 7,2,3,6,5,4. All pairwise comparisons between array elements happen during the merging of two lists, one with lower indexed items (the left list) and one with higher indexed items (the right list). If you run top-down mergesort on this array, the 5th pairwise comparison will compare from the left ist with from the right list. Please answer with just a single number, from 1 to 8, I am not sure how forgiving this system is in terms of formatting tolerance D Question 2 1 pts You are running mergesort on an array with the contents: 1, 8, 7, 2, 3, 6, 5, 4. All pairwise comparisons between array elements happen during the merging of two lists, one with lower indexed items (the left list) and one with higher indexed items (the right list). If you run bottom- up mergesort on this array, the 5th pairwise comparison will compare kfi lii witi to 8, I am not sure how forgiving this system is in terms of formatting tolerance. from the from the right list. Please answer with just a single number, from 1