She starts writing out the program to do this (check if a vector of integers is sorted in descending order), but suddently, someone comes a long and deletes part of her code! Below is what she has left. 1 2 3 4 5 6 // Checks if a vector int> called elements' is sorted in // descending order. That is: // {1, 2, 3, 4} returns false, because it's sorted but increasing. // {4, 3, 2, 1} returns true, because it's sorted and decreasing. bool isSortedDescending(const std::vector??>& elements) { for (int i = 0; i