Vegetables often contain oil, the problem is getting omega-3's, which our bodies can't make.

In the sea, it's algae who're producing it: then krill, then squid/fish/etc eat them..

some plants make it, some don't..

olives are good, olive-oil, etc..

but anybody who's eating squash is getting omega-6's or 9's, even though it seems non-intuitive.