References:

10 - If you filled a pool with liquid oxygen, would you be able to breathe in it?

https://education.jlab.org/qa/liquidoxygen_01.html

https://www.quora.com/Can-humans-breathe-liquid-oxygen

9 - What would the world be like is religion never existed?

https://www.quora.com/How-does-religion-influence-the-society-we-live-in

http://www.freedommag.org/issue/201412-expansion/l-ron-hubbard/religious-influence-in-society.html

8 - Where would mankind be if the wheel was never invented?

https://www.smithsonianmag.com/science-nature/a-salute-to-the-wheel-31805121/

http://www.ancient-origins.net/ancient-technology/revolutionary-invention-wheel-001713

7 - How do cats purr?

https://www.mnn.com/family/pets/stories/why-do-cats-purr

https://www.loc.gov/rr/scitech/mysteries/catspurr.html

6 - Why do we get “morning breath”?

http://www.medicaldaily.com/your-morning-breath-explained-what-causes-it-and-how-you-can-treat-it-312046

https://ultradex.co.uk/how-to-stop-morning-breath/

5 - How long would it take to successfully colonize Mars?

https://www.quora.com/How-long-will-it-take-for-humans-to-colonize-space

https://image.gsfc.nasa.gov/poetry/venus/q2811.html

4 - How would humanity evolve if we only had one gender?

http://www.second-opinion-doc.com/a-guide-to-animals-which-can-change-sex.html

https://www.quora.com/What-would-happen-if-all-males-died-out-in-one-day-including-the-unborn-How-would-it-compare-with-all-the-females-dying-out-How-would-the-world-change-How-would-society-and-laws-change

3 - Can you over boil an egg?

https://www.quora.com/Can-you-over-boil-an-egg

https://www.simplyrecipes.com/recipes/how_to_make_perfect_hard_boiled_eggs/

2 - Why are cats afraid of cucumbers?

https://www.bustle.com/articles/124691-why-are-cats-afraid-of-cucumbers-it-may-seem-funny-but-heres-why-you-shouldnt-pull

http://www.iflscience.com/plants-and-animals/cats-are-completely-terrified-cucumbers-why/

1 - Why do your ears pop when you yawn?

https://www.drweil.com/health-wellness/body-mind-spirit/ears-nose-throat/ears-popping-too-often/

http://www.physics.org/article-questions.asp?id=135