Layers

Lets play a game.
What do all these things have in common?

Onions, 7 layer bean dip, photoshop™ files, your uncle wearing 3 lightweight sweaters, dual layer dvds, the earth, baklava, cake, discord, parking structures and ogres.

A: Balloons
B: Nitrogen
C: The inevitable death of the universe
D: Layers

TIMES UP
YOU'RE WRONG

It's layers