Amazon Software Development Engineer Intern interview questions

It was good my first interviewer didn't showed up my interview was rescheduled second interviewer was nice and supportive but I don't understand on what basis they have selected students

There are 3 online assessments that we have to complete. The first round is a debugging challenge consisting of 7 questions where you have to make minor changes to the code. The second round is a coding challenge where you are given two coding questions. In the third round, you are given in a workplace simulation where the questions are mostly based on how you would handle the workplace environment.