Does Congress even understand Facebook?

After spending five hours in front of the Senate on Tuesday, Facebook CEO Mark Zuckerberg spent Wednesday testifying before the House, where the 33-year-old billionaire found a much more hostile audience.

Zuckerberg faced questions about the future of his company. Lawmakers launched a range of criticism, including the apparent lack of diversity in the company's managerial ranks.

Many of the questions revealed some confusion about how Facebook works.

On Tuesday, Sen. Orrin Hatch, R-Utah, who is 84, didn't seem to know how Facebook, which is free to use, can make money.

"How do you sustain a business model in which users don't pay for your service?" Hatch asked.

"Senator, we run ads," Zuckerberg said with a smile.

Rep. Markwayne Mullin, R-Okla., repeated a question to Zuckerberg he had been asked over and over.

"How can someone control keeping the content within the realm they want it to without being collected?" Mullin asked.

"If you don't want any data to be collected around advertising, you can turn that off and we won't do it," Zuckerberg said.

And a question from Dave Loebsack, D-Iowa, betrayed a misconception about what Facebook does with user data.

"Is it possible for Facebook to exist without collecting and selling our data?" he said. "Is it possible to exist?"

"Congressman, we don't sell people's data," Zuckerberg said. "I think that's an important thing to clarify upfront."

Some lawmakers accused the social media giant of political censorship, pointing to a recent ban imposed on Trump supporters Diamond and Silk. Zuckerberg told Rep. Joe Barton that a Facebook team "made an enforcement error" in that case.

At the heart of the hearings were the recent revelations that data from as many as 87 million users wound up in the hands of data-mining company Cambridge Analytica, which was linked to the Trump campaign. Zuckerberg admitted that his information was included.

While the tech tycoon insisted that new protections are in place, he acknowledged government regulations may be needed.

"The internet is growing in importance around the world in people's lives and I think that it is inevitable that there will need to be some regulation," Zuckerberg said. "So my position is not that there should be no regulation but I also think that you have to be careful about regulation you put in place."

But for many lawmakers, Zuckerberg's carefully worded answers fell short of addressing the platform's security settings and the increasing concerns about making privacy a priority.