True or False: Custom functions can be applied to conditional formatting in Google Sheets.

Custom functions can indeed be applied to conditional formatting in Google Sheets, which makes this statement true. Google Sheets allows users to create personalized functions through Google Apps Script, which can be utilized in conditional formatting rules. This means that if you have a specific condition that you want to highlight in your spreadsheet, you can write a custom function that encapsulates that logic.

On the other hand, while default functions are readily available for use in conditional formatting, the flexibility of custom functions allows for much more tailored and specific conditions, beyond what is provided by the default options. Therefore, the correct choice highlights the enhanced capabilities available within Google Sheets, making it possible to apply custom logic to format your data dynamically.