Very beautiful song and easy to grasp after just a few lessons. Thanks for sharing!
There was an old Soviet slogan for children: "Sun, air, and water are our best friends". This exercise reminded it strongly.
In English, whenever you have a list of more than two words [for example: sun, wind, and water], you put a comma between each and before "and". Is this different in Swedish?
Actually, it's rare to find a comma before the "and" in English, except the US. Funnily enough, it's called 'The Oxford Comma', because it's used in Oxford (but rarely elsewhere in the UK). There's a pretty cool TED talk about it, if you're interested. http://ed.ted.com/lessons/grammar-s-great-divide-the-oxford-comma-ted-ed
Yes, in Swedish there is never a comma before the final "and". Ett, två och tre.