You really didn't know the answer? You thought they just threw 38% of the cow into a landfill or something? You didn't know where leather came from? You've never once heard of bone meal? Gelatin?
I suppose I had to pick between woefully ignorant and disingenuous. Did I pick the wrong one?
Edit: Insert to insert this link. http://www.mindbodygreen.com/0-1559/...tle-Image.html