What is the main difference between shell sort and insertion sort? Shell sort is less efficient because it calls insertion sort repeatedly Insertion sort performs better on arrays that are mostly sorted while shell sort performs worse on such arrays. Insertion moves entries only to adjacent locations, while shell sort allows items to leap from one positon to another. Shell sort makes fewer passes than insertion sort How many passes(i.e. scaning through an array) does the selection sort make to sort an array of size 10 ? 9 11 10 100 .