Can I retest all questions without losing my previous data?
Yes! With the new Test History feature, you are able to decide if you want to Test Incorrect items (as ESGI has worked in the past) or Retest All items on a test.
If you do not see the choice when you click "Test", it is probably because it is the first time you are testing. Another reason could be that it is a test in a subject tab that is managed by your school or district, and they have selected whether they want you to Test Incorrect or Retest All for the tests in that Managed Subject Tab.