Facebook CEO Mark Zuckerberg has endured a gruelling five-hour hearing before the US House of Representatives, facing tough questions about how the site protects user data, whether it is biased against certain users – and what, exactly, it is.

The second day of questioning before the House Committee on Energy and Commerce proved more taxing for the 33-year-old than his testimony before two Senate committees on Tuesday. Representatives shot rapid-fire questions at the entrepreneur, and even interrupted his answers at several points.

“While Facebook has certainly grown, I worry it has not matured,” Representative Greg Walden said at the opening of the hearing on Wednesday. “I think it is time to ask whether Facebook may have moved too fast and broken too many things.”

Much of the discussion surrounded Facebook’s handling of user data and privacy – a relevant line of questioning, as the meeting was called primarily to address the Cambridge Analytica scandal, in which a consulting company accessed millions of Facebook users’ data without their knowledge.

Mr Zuckerberg answered questions on a range of privacy issues, from third-party access to the creation of fake profiles. He reiterated several times that Facebook does not sell users’ information to advertisers.

Mark Zuckerberg says his personal data was sold to 'malicious third parties'

In one particularly pointed exchange, Representative Frank Pallone asked Mr Zuckerberg to answer, with a “yes” or a “no,” whether he would change Facebook’s default privacy settings to collect the minimum amount of users’ personal information possible.

“This is a complex issue that deserves more than a one-word answer,” Mr Zuckerberg said.

“That’s disappointing to me,” Mr Pallone responded.

How to stop Facebook from revealing everything about you Show all 9 1 /9 How to stop Facebook from revealing everything about you How to stop Facebook from revealing everything about you Lock your profile down If you haven’t done this already, do it now. In Settings, hit the Privacy tab. From here, you can control who gets to see your future posts and friends list. Choose from Public, Friends, Only Me and Custom in the dropdown menu. How to stop Facebook from revealing everything about you Limit old posts Annoyingly, changing this has no effect on who’s able to see your past Facebook posts. Instead, on the Privacy page, you have to click on Limit Past Posts, then select Limit Old Posts and finally hit Confirm on the pop-up. How to stop Facebook from revealing everything about you Make yourself harder to find You can stop completely random people from adding you by selecting Friends of Friends from the dropdown menu in the Who can send you friend requests? section of the Privacy page. It’s also worth limiting who can find your Facebook profile with your number and email address. At the bottom of the page is the option to prevent search engines outside of Facebook from linking to your profile. How to stop Facebook from revealing everything about you Control access to your Timeline You can limit who gets to post things on your Timeline and who gets to see posts on your Timeline too. In Settings, go to Timeline and Tagging and edit the sections you want to lock down. How to stop Facebook from revealing everything about you Block people When you block someone, they won’t be able to see things you post on your Timeline, tag you, invite you to events or groups, start conversations with you or add you as a friend. To do it, go to Settings and Blocking. Annoyingly, you have to block people on Messenger separately. You can also add friends to your Restricted list here, which means they’ll still be friends with you but will only be able to see your public posts and things you share on a mutual friend's Timeline. How to stop Facebook from revealing everything about you Review tags One of Facebook’s handiest privacy features is the ability to review posts you’re tagged in before they appear on your Timeline. They’ll still be visible on the News Feed while they’re fresh, but won’t be tied to your profile forever. In Timeline and Tagging, enable Timeline review controls. How to stop Facebook from revealing everything about you Clean up your apps You can view a list of all of the apps you’ve connected to your Facebook account by going to Settings and Apps. The list might be longer than you expected it to be. It’s worth tidying this up to ensure things you no longer use lose access to your personal information. If you don’t want to log into websites and apps with your facebook account, scroll down and turn Platform off. How to stop Facebook from revealing everything about you Change your ad preferences You can view a list of everything Facebook thinks you’re into and tinker with your ad preferences by going to Settings and Adverts. A lot more information is displayed on the desktop site than the app, so we’d recommend doing this on a computer. How to stop Facebook from revealing everything about you Download your data Facebook lets you download all of the data it has on you, including the posts you’ve shared, your messages and photos, ads you’ve clicked on and even the IP addresses that are logged when you log in or out of the site. It’s a hell of a lot of information, which you should download to ensure you never over-share on the social network again.

The entrepreneur’s answer was typical of his noncommittal, vague responses throughout the day. He declined to endorse any specific policy proposals during the hearing, though he did say it was “inevitable” that the internet would have to be regulated.

Senators Edward Markey and Richard Blumenthal introduced “privacy bill of rights” legislation to the Senate shortly before the hearing began. The act would require “edge providers” like Facebook and Google to obtain opt-in consent to use customers’ personal information. It would also force them to protect that information with “reasonable” measures.

Mark Zuckerberg denies Facebook market monopoly: 'It certainly doesn't feel like that to me'

Mr Zuckerberg faced pointed questions about the Cambridge Analytica scandal, in which the political consulting firm accessed data from up to 87m Facebook users – some of them without their consent. The data was collected and sold to the company by Aleksandr Kogan, a professor at Cambridge University.

On Wednesday, Mr Zuckerberg revealed that his own data had been accessed by Cambridge Analytica. He also said the data may have been sold to “a handful” of other firms as well, though he declined to mention their names. He claimed Facebook has asked these companies to delete the data in 2015, but that they may have retained it anyway.

Asked whether Facebook planned to sue Mr Kogan or Cambridge Analytica, Mr Zuckerberg said: “it’s something we’re looking into.”

Cambridge Analytica has denied breaking any laws, and said they properly licensed the data from Mr Kogan’s research company.

11 useful Facebook features you didn't know existed Show all 11 1 /11 11 useful Facebook features you didn't know existed 11 useful Facebook features you didn't know existed Clean up your News Feed Most of us are Facebook friends with some people we don’t actually care about, and there are several ways to keep their updates off your News Feed. The easiest option is to head to the column on the left and open News Feed Preferences. From here, you can prioritise friends, unfollow friends, refollow friends you unfollowed in the past and even block specific apps. 11 useful Facebook features you didn't know existed Change ad preferences You can view a list of everything Facebook thinks you’re into and tinker with your ad preferences. A lot more information is displayed on the desktop site than the app, so we’d recommend doing this on a computer. Just open Settings and select Advert Preferences. 11 useful Facebook features you didn't know existed Manage notifications You can get notifications about pretty much anything on Facebook these days, and that can be seriously irritating. Choose what you do and don’t want to be notified about by going into the Settings menu and selecting Notifications. You might be surprised by the number of sections you have to trawl through. 11 useful Facebook features you didn't know existed Save data Facebook automatically plays videos in your News Feed, and that’s a problem if you aren’t on a generous data plan. You can change this by going to Videos in the Settings menu and disabling autoplay. On the app, there’s feature in the left-hand column called Data Saver, which also does this, but reduces the size of pictures too. 11 useful Facebook features you didn't know existed Reorder your News feed You can choose to order the updates that appear in your News Feed by time or importance. Just hit the three buttons next to News Feed Preferences on the Facebook site and choose between Top Stories and Recent Stories. 11 useful Facebook features you didn't know existed Download your data Facebook lets you download all of the immense amounts of data it has on you, including the posts you’ve shared, your messages and photos, ads you’ve clicked on and even the IP addresses that are logged when you log in or out of the site. It’s a lot of information, which you’ll want to get your hands on if you decide to quit the social network. 11 useful Facebook features you didn't know existed Find nearby places Nearby Places is actually a really handy tool, which lets you quickly find and research things like restaurants, hotels, museums and nightlife hotspots around you. It lives in the left-hand column, and also shows useful information like customer ratings, prices and distance. 11 useful Facebook features you didn't know existed Find free Wi-Fi Similarly, Find Wi-Fi is ideal for when you’re bored, running low on data or lost. It shows you all the places in your vicinity that offer free Wi-Fi, so you can head over and either relax or get some work done. 11 useful Facebook features you didn't know existed Save things for later Facebook’s ideal for killing time, but every now and again you’ll stumble across something you’re interested in right as you need to put your phone away. Fortunately, you can save posts for later by hitting the arrow in the top-right corner and selecting the Save option. Everything you save goes straight to the Saved section in the left-hand column. 11 useful Facebook features you didn't know existed Control tags When people tag you in posts or pictures, they don’t have to automatically appear on your profile. You can switch on Facebook’s Review Tags feature by going to Settings and Timeline and Tagging. 11 useful Facebook features you didn't know existed Delete your account To permanently delete your Facebook account, you need to head to Facebook’s Delete Account page. The site can take up to 90 days to process account deletion requests, but once your account's gone, it’s gone. You can deactivate your account instead, by going to Security and Login in the Settings menu.

Mr Zuckerberg also faced a smattering of questions on other topics, including whether Facebook censored conservative voices on its platform. Several lawmakers brought up the case of video bloggers Diamond and Silk, who have complained that Facebook limited the reach of their videos and told them their content was “unsafe to the community”.

Representative Marsha Blackburn – a Republican whose campaign ad about “the sale of baby body parts” was temporarily blocked by Twitter last year – asked Mr Zuckerberg if Facebook manipulated its algorithms to prioritise or censor certain forms of speech.

“There are types of content like terrorism that I think we all agree we do not want to have on our service,” Mr Zuckerberg replied. “So we build systems that can identify those and can remove that content and we’re very proud of that work.”

“Let me tell you something right now, Diamond & Silk is not terrorism,” Ms Blackburn responded.

Mr Zuckerberg also responded to questions about whether he thought Facebook was a monopoly. He replied that he did not, and said that Americans used many other apps to communicate with each other. He failed to mention that Facebook owns three of the top 10 mobile apps used in the US, according to the data analytics site comScore.

At one point, Representative Greg Walden asked Mr Zuckerberg what, exactly, the massive company he had built was.