Margerie
You asked about balance. Everything contains fats grass flowers wheat insects animals etc. How much and what alters. The amount of omega three and six in green things and root vegetables is in very approximate terms about equal but a small proportion a few parts per thousand.
We get it by eating it.
Seeds (including wheat) have more 1-2% but are generally high in omega six with limited exception eg flax.
Nuts have quite high levels of fats of which quite a lot is omega six. Walnuts contain a little omega three.
Meat and chicken contain quite a lot of fat but only a small proportion is omega three and six.
The mother fat is found in green things seeds nuts etc.
The daughters DHA and EPA are only found in living things, and only in really significant amounts in oily fish.
This site lets you look food contents up.
http://www.nutritiondata.com/topics/fatty-acids
You have to label read and watch out for vegetable oils, what type etc. It is a bit of a pain to start but I soon got the gist of good watch and bad in terms of omega three six balance.
RB