To Split mp3 Files for my player

Not necessarily of much use to anyone else, but here it is for posterity.
Problem: It is difficult to rewind a short time in my (admittedly cheap) mp3 player. [1] I need to do this often, since I walk along busy roads, and have kids.
[1] A note on cheap: It was a gift. It was within [...]

Facts

Apparently from a recent article in Science magazine.
I saw similar statements in Scientific American.
• We use about one litre’s worth of fossil fuels to grow, harvest, process and transport a litre of corn-base ethanol.
• Substituting just 10 % of fossil fuels to biofuels for all vehicles would require about 40% of the entire cropland in [...]