Embedded drop down list

Hello everybody,

I was recently relocated at work and the job position I inherited had work done on a spreadsheet. In the spreadsheet several cells have drop down list (when a cell is selected, a down arrow appears with a list to choose things from). I am finding a few things of the dropdown list is incorrect. In Excel 2010, I click the data tab on the ribbon, then data validation, and in the settings tab, I see Allow is set to "list", Data is set to "between", but the source is not telling me where the list is.

My question is, how to find the list so I can edit the items that are incorrect. I do not need to delete anything, just edit.

Thank you all and any help that any body can give would be greatly appreciated.