If multiple options for Terms of Service/Terms and Conditions appear on a Registration Form and you only want one to appear, it could be a case of having more than one option enabled.
Terms of Service:
There is a Terms of Service Agreement option that can be set as a Global settings.
This can be enabled/disabled in the Members > Data Privacy > Settings section.
There is also a Terms of Service field that can be added to a Custom Registration Form on a per Level basis.
This can be found in the Advanced Options > Registrations > Custom Forms *Click on Custom Registration Form* section.
Terms and Conditions:
There is a Require Terms and Conditions setting in the Setup > Levels > *Click on Level Name* > Requirements section.
We recommend checking those options if you are seeing more than the desired Terms of Service/Terms and Conditions options on a Registration Form.