The way to answer open questions and closed questions is different. With an open question there are many possible answers, and it is natural to give a fairly long answer. However, with a closed question the answers are limited and often you could answer with just yes or no. So, with these questions short answers are the best.
If you plan to take a speaking test, such as IELTS or TOEFL, it is important to understand the difference between open and closed questions, and how to answer them. Take a look at the video for some examples.