Hey there!
I believe your answer will be the "Shift" key. You can hold down Shift and select a cell from your current cell position to select everything between the original position and the cell you clicked on without having to drag your mouse across the cells. If you were to hold down the Ctrl or Command key, you would only have your original selection and your new selection highlighted.
Your answer will be Shift.
Hope this helped you out! :-)
