I don't disagree - but energy, mining, and forestry are also fundamental parts of the economy (with transportation, construction, and manufacturing on the level

I don't disagree - but energy, mining, and forestry are also fundamental parts of the economy (with transportation, construction, and manufacturing on the level just above those), and if we're talking about giving kids a rudimentary insight of the mechanics and economy of this big system in which we all live, I don't see any reason to stop at agriculture.