Hi, In any CBT (Computer based Test) review marking facility is available and you mark question and then go to other segments/ parts of examinations and after attempting that part you can come back to past segment and finish it off. you can also remove your answer if you have any doubt in answer.

Also it is subjective and depends on examination to examination. Could you please specify which examination are you concerned about? It would be highly helpful for us to answer you more accurately.

All the Best!!!