That's what my six-year old asked today, while playing Plants vs Zombies on my i-phone. He's always been a curious boy.
Newsletter
Sign up for our email newsletter for the latest science news
More From Discover
Recommendations From Our Store
Shop Now
Stay Curious
Subscribe
To The Magazine
Save up to 70% off the cover price when you subscribe to Discover magazine.
Copyright © 2023 Kalmbach Media Co.