A select one question by default will only allow users to select the answers available in the choices sheet.
If you want them to have less selections available, you can apply a choice filter (e.g. if one question selects a country, the next question uses a choice filter to reduce the list to cities in that country).
If you want them not to be able to edit the question, you can make it read only.
If you want them to be able to edit the question, but also not edit the question after they've selected the answer... we'll probably need more information about what you are doing e.g.:
- Survey123 Connect (desktop) or the web form designer
- Workflow
- Sample questions and expected progression through the form
You can have some questions read only and calculated based on information entered into other questions. You can also hide these questions.