Why Vegetables?

I guess this answers it all.
I love graphic visualization of data.

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35% of our food consumption comprise of vegetables. Fruits are a fierce competitor but some how I do not feel that food constitutes part of the core diet. Of course if you don't eat fruits you will also get things like scurvy. However, fruits always feel like a luxury to me. I wonder if I can find books to justify this.

This graph was created using the AVA data on their website and it assumes per capita consumption using the population at the time. Therefore it assumes everybody in the population consumes pork when it doesn't. I'm just glad everybody consumes vegetables, even those carnivorous ones amongst us.

Why vegetables?
1) push for vegetarianism justified?
2) only food item consumed by all, no cultural or religious food taboos, only personal preferences variation
3) large percentage of our consumption by quantity and volume
4) large percentage of our import by volume but not by value as meat is more expensive to produce and consume. Understandably because they have to produce vegetables to feed the animals first before feeding us. Yet another reason to study vegetables - link to point (1)
5) large volume of perishable vegetables - does vegetables have to be fresh and therefore must have a nearby source? still need to be verified.

I'm still trying to pin down one hardcore objective in my research rather than flying all over the place but it's been hard. I've been greedy.

Questions:
1) Do we really have an impact on vegetable productions in exporting countries?
2) Or do producing countries have more impact on us?
3) Does environmental degradation and change affect domestic population more than food-dependent importing countries like Singapore?
4) Who has the power in affecting the environment of agricultural production?
5) Do the different types of production method and external intervention make a difference?
6) Can adjusting consumption practices really improve conservation (environmental quality of farming area)?

Methods:
1) Quantify environmental quality
2) Understand processes that affect environmental quality
3) Answer above questions through data collected from (1) and (2)