What's also amazing is how any gene gets expressed - imagine how the cell needs to find any particular gene within the long thread of DNA (coiled even!) and get it transcribed.
Ah, this is a good one - no one got it. The answer is: Springs for making a regular chair into a rocking chair, they mount onto the bottom of the front legs.
Here's the winning entry, picked by the master of Bizarro himself Dan Piraro: #22 by Chris Williamson. Congrats, Chris! You've got the free t-shirt!