Actually, it's only the US and the UK basically that still use the old inch/feet length system, pounds/ounces for weight, gallons for volume, and so on.. the rest of the world use the metric system. Not sure about Canada (that's where Zerlina is from), but I can imagine they'd be using the metric system, not the US/UK one.
Celsius is as far as I know also more widespread than Fahrenheit, can't think of much else than a couple of English speaking nations using Fahrenheits, but I'm not too sure. We use almost only Celsius in Europe as far as I know. Celsius makes a lot more sense too. Fahrenheit was based on that the absolute minimum temperator should be at 0 (when the guy came up with it, 0 F or about -18 C was the absolute lowest temperature he could reproduce in experiments)
It's a lil off topic, but yeah. Still Zerlina, you can't blame Americans for using the system they are taught and in most cases the only one they know (no offense, I mean, most ppl in countries that use metric/Celsius don't know how to convert to US/UK system and Fahrenheits either).