Jenny and Greg
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Jenny puts scientist Greg Foot to the test

17 January 2014 Last updated at 08:21 GMT

Daredevil scientist and TV presenter Greg Foot got put to the test when he popped into Newsround.

He answered some of those burning questions we have like what makes us yawn? And are zebras black with white stripes, or white with black stripes?

To make it all the more trickier Newsround only gave him 60 seconds to see how many he could answer.

Check out the clip to see how Greg did...