It’s been said that "necessity is the mother of all invention," but this example shows how human greed has it’s part the birthing process.  Why was there a "shortage" elephants?  Well, because we’d been killing them for their ivory tusks.  Why did we need their tusks?  Well, to make billiard balls and piano keys.  Why did we need those things?  Well, we didn’t really, but we wanted them.

Greed is further displayed in the many uses that were developed for celluloid, even though it was a highly flammable and thus dangerous substance.

Reflection:

Think about other products you’ve heard of that went on the market before they’d been properly tested for safety.

Look for things in the news that show examples of human greed.