Hi there Shagun! Are you referring to AP-style question exams or the general practice quizzes? In both cases, you can filter the questions down by unit!

For AP-style question exams, you can use the dropdown in the upper left corner of the question box in Exam Simulation mode to select the unit you'd like. For general practice quizzes, you can also similarly filter questions using the dropdown that is labeled "All units".

Hope that helps! We look forward to any additional feedback you may have :D