Smoking causes cancer but cures salmon?!

Nominative determinism; can cold showers ward off coughs and flu; what's von Willebrand's Disease; if smoking causes cancer how does it cure salmon; why can some people roll their tongues; what's "Agent Orange"; in television, how does a green screen work; do crocodiles age more slowly than we do; what is Helicobacter pylori? Chris and Lester have the answers...