If you're using Google Slides and want to hold a Q&A, you can display a short URL on your presentation that attendees can go to and submit a question without interrupting the proceedings. At that same URL, anyone in the audience can see all the questions that have been submitted thus far and give them a "thumbs up" to indicate interest in hearing an answer.
From the presenter's perspective, the device that's running their presentation will have access to all the questions that come in, and you can sort them based on those that receive the most votes. Google has also added a few new features to make it easier to share a Slides deck if you're not using a standard PC -- you can now send your presentation to a screen via the Hangouts app when using an iOS or Android device. All told, you can now use either Hangouts, Airplay or Google Cast functionality to get your presentation off your phone or tablet to a screen.
Lastly, there's a new "laser pointer" feature for when you're presenting on a computer over the web that lets you quickly point out content onscreen for your audience -- it basically turns your mouse pointer into a laser pointer. All of these updates should be available today, whether you're using Slides in Chrome or the apps for iOS and Android.