Topics: Ask an American-Saving the oldest photograph; law versus rule versus policy; to stem from versus to be derived from; bring it on; infomercial; hawking; exercise fad

Words:
studio
to show (something) off
luminous
three-dimensional
nanoparticle
to scatter
nanotechnology
unwittingly
degradation
to corrode
chemical mechanism
to preserve
law
rule
policy
to stem from
to be derived from
bring it on
infomercial
to hawk
exercise fad