June 25, 2015 6:25 AM EDT

Why do we laugh?

Scientists think laughing evolved to promote social group activity–you laugh 30 times as much when you’re with others

Why is a Cheerio a circle?

The “o” matches the cereal’s name, which was originally CheeriOats when it debuted in 1941

What are we most afraid of?

One study found that Americans’ biggest personal fear–even more than public speaking–is walking alone at night

Why do we scar?

We can grow only 1 mm of epithelial tissue a day to seal our wounds, so our bodies hurriedly release collagen to patch the skin

How much does a ticket to space cost?

A flight aboard Virgin Galactic retails for $250,000

How do fetuses breathe?

They don’t. Pregnant women consume up to 20% more oxygen, which is delivered to fetuses through the placenta and umbilical cord

SOURCES: ETHOLOGY; GENERAL MILLS; CHAPMAN UNIVERSITY SURVEY ON AMERICAN FEARS; NBC NEWS; VIRGIN GALACTIC; GLOBAL LIBRARY OF WOMEN’S MEDICINE

This appears in the July 06, 2015 issue of TIME.

Contact us at letters@time.com.

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