Where does beer come from?

I was chatting with a friend who teaches at an International School (students from foreign countries) recently. She related a classroom incident that really had me in stitches. She was teaching the class about the food pyramid. Interestingly, one of the items that the kids of 7 years old had to put into the right category of the food pyramid was beer! So one little girl was having difficulty on where to put the beer. Which category does the beer go into? To guide the little girl out, my friend said:

Teacher: Well, to know which category the beer goes into, we must first know where does beer come from. What is it made of? Do you know where does beer come from?

Girl 1: Ah, beer? Hmm...beer ah, comes from olive oil (for the yellow) and GAS for the bubbles.

To the dismay of the teacher, everyone was laughing and jeering by now. Teacher (my friend) noticed one particular little girl had the disgust look on her face to show that SHE knows the answer to the question. So teacher calls on second girl...

Teacher: Girl 2, can you please help Girl 1 with this question then? Do you know where does beer come from?

Girl 2: Of course I do! Beer comes from TIGERS!

By now my friend is rolling her eyes to the ceiling!!! The classroom is in an uproar! Lots of whispers are doing their rounds on how silly the girls were. While trying to calm the class down, teacher now resume the conversation:

Teacher: I see. Does your father drink Tiger Beer at home?

Girl 2: Yes, he does.

Teacher: Ok, but how is it possible that the beer comes from tigers? I mean how?

Girl 2: You see teacher, if cows can give milk to their young, why can't tigers give beer to their young?

Wow...my friend was bowled over with this irrefutable logic!

This is hilarious and I can't stop laughing! So my friends, WHERE DOES BEER COME FROM?