What is a characteristic of sequential-access files during data updates?

A characteristic of sequential-access files during data updates is that they often overwrite existing data. This is due to the nature of how sequential-access files are structured; they are designed to read and write data sequentially, which means that when new data is written, it typically goes into contiguous blocks. If the new data needs to update information at a specific point, the existing data in that location is replaced or overwritten.

In contrast, options that suggest updates occur without risk or imply random access do not align with the properties of sequential-access files. These files do not allow for random access; rather, you must read through data sequentially to reach the area where you want to make an update. Additionally, the notion of all data being automatically saved as backups does not reflect a characteristic inherent to sequential-access files, as backup processes vary significantly based on the file management system employed and are not a direct feature of sequential access itself.