I expect you to listen to the questions and to make a good faith effort to answer them. If you do not know how to answer a question you may simply say so and I will either ask you another question or ask another student to assist us. It is fine to be incorrect or hesitant in your answers. Often the best learning in class comes from exploring uncertainty or walking through the steps that lead to a wrong answer. Each student should participate in class discussions.
Some people find speaking in class much easier than do others.
If you tend to be quiet in class you should push yourself to raise your hand to join the discussion. If you are a regular participant you should limit the frequency of your comments to allow others to participate. A rule of thumb is not to volunteer more than one or two comments per class. Some people are more likely to volunteer a comment when there are fewer hands raised, or when there is a gap in the discussion. In calling on students who raise their hands, I try to call first on students who participate in the discussion less frequently.