Sound waves are waves where whole atoms move. Electromagnetic waves are where only electrons are part of the wave. But science today has relativity and quantum which don't really make sense, because they are just a twisted way to get the right answer and not a real understanding of what is really going on.
The reason people in Europe have lots of diesel and in the US they don't is funny US regulations. The US smog limits are per gallon of fuel and the European per mile driven. Diesel is much heavier than gas, so has more stuff in each gallon burned, but more energy too. If the US rules were per pound of fuel or per mile driven then Diesel would be popular like in Europe.
I am convinced that Vitamin D is important for resisting the flu. It is produced in your skin from sunlight. It is important for your immune system. During the winter most people don't get enough, which seems to be why the flu is more common then. Very young and very old people get even less sun than normal and are worse hit by the flu. The same flu virus is not nearly as deadly during the summer. The recommended daily allowance of Vitamin D was calculated to be enough keep people from getting rickets but is far below what your body will produce given 15 minute of sun. http://www.virologyj.com/content/5/1/29 http://en.wikipedia.org/wiki/Flu_season#Mechanism_for_seasonal_nature_of_influenza (yes I added the Vitamin-D stuff but look at the links)