It is important to include column or row headings and mark them as headers when sorting data in spreadsheets because it helps maintain the context and meaning of the data. By marking them as headers, the sorting algorithm in the software will recognize them as separate entities from the actual data, ensuring that the headings remain at the top of the columns or left of the rows. This way, users can easily reference which column or row corresponds to which data set, and the data remains organized and easy to understand even after sorting.
