Answer:
True.
Step-by-step explanation:
If the input message is omitted when creating a data validation rule for a cell, no message will appear when the user selects the cell. Data validation rules are used to define the type of data that can be entered into a cell, and the input message is an optional feature that allows you to provide a custom message to the user when they select the cell. If the input message is not specified, no message will be displayed when the user selects the cell.