There are two types of questions, Review and Exam.
The Review Questions will both show you that you answered incorrectly and give you the right answer.
The Exam Questions will only show you that you answered incorrectly as you answer them. While you cannot change your answer once you submit it after starting the exam, you can make a note which questions you got wrong and study those on the second time through the exam.
You can take the exams as many times as you need until you pass them.