Questions is a fairly new feature of Google Classroom that I have not used in my class. I've explored it a bit and I think they would be great for things such as bell ringers or exit ticket questions. Basically you can ask a question, give some multiple choice answers or let them type in their own answer, and then have them turn it in.
You can set it up so that students can see other responses and respond to them, or if you'd like to not allow them to see others, you can hide the respond to each other option, which also hides each answer. It also doesn't let them see other student's answers until they answer, which is nice.
To ask a question, follow these steps:
1. Navigate to the class you'd like to ask the question in.
2. From there, click on the plus sign in the lower right hand corner. Choose "Create Question."
3. A window should pop up that looks like this:
4. Fill in the question in the question blank and give any additional directions you'd like. Choose a date it is due and the type of question. You're two choices is short answer or multiple choice. If you choose multiple choice, it will allow you to write in the answers you'd like the students to choose from. Decide whether or not students can reply and see each others answers and also whether or not students should be able to edit their answers. In the example of above, the students ARE able to reply to each other, but are NOT able to edit each other's answers.
5. Attach any documents you'd like to using the buttons along the bottom, then click ask.