To copy a question from another assessment into your quiz, rather than simply linking to it, click Import Question on the Add Question screen tool bar. The copied question is not linked to the original content. Changes made to the original question will not change the copied content.
On the Import Questions pop-up screen, click the Content drop-down and select an existing quiz. The questions from that quiz will appear in the Question list.
Use the check boxes at left to select the question(s) you wish to import. The pop-up screen will close and the added question will appear in your quiz's edit screen.
You can click the Edit Question button in the tool bar to change the question properties, apply a different points value, etc.
Multiple choice multiple answer
Add a question from a question pool