"You are made of polymers, and so are trees and telephones and toys. A polymer is a long chain of identical molecules (or monomers) with a range of useful properties, like toughness or stretchiness -- and it turns out, we just can't live without them. Polymers occur both naturally -- our DNA is a polymer -- and synthetically, like plastic, Silly Putty and styrofoam. Jan Mattingly explains how polymers have changed our world." View the complete lesson at TED-Ed.