It seems as if we didnt evolve alone as if we are connected to the earth in itself. I am having a hard time presenting my question, so I apologize for it. My point is, If we evolved, then the plants also evolved.
That's the general idea. There are many dependent and co-dependent systems in nature that evolutionary biologists have dissected. Just because two or more systems are dependent or co-dependent does not rule out evolution - in fact in many cases they strongly support evolution. Dawkins lectures on this subject in "The Ultraviolet Garden" portion of his "Growing Up in the Universe" series.
How come the plants have things we need.
We eat them (and then only the ones) which have the ones we need. They do not supply 100% of everything we need, and we do not eat 100% (or anywhere close) to the available plant varieties on earth. We must also eat other sources of fat & protein including meat to have a healthy diet. Some plants not only don't supply what we need, some are of course very harmful. In some lands inhabitants have to boil certain foods multiple times in order to remove toxins from them. Plants just offer a large 'grocery store' of organic compounds, some of which we can use, and some we must avoid.
For some plants it is evolutionarily beneficial for them to be toxic (fewer things eat them, and thus, they survive).. and for others it has been evolutionarily beneficial for them to produce large, eatable fruits (humans and their ancestors farm them, and thus, they survive).
Some animals eat dirt, or engage in other behaviors in order to get all the nutrients they need. These behaviors survived because the ones that performed them survive and the ones that didn't got weak and died off.
It is as if the plants were designed for us, otherwise why do they have the exact nutrients that we need to survive.
If an animal could not survive off of what exists on earth - be it plants, animals, fungi, algae, etc... then that species would die, and thus would not be here. As Dawkins points out... plants are not here for our benefit, nor are animals there for plants benefit (though they do benefit from animals in various ways). We evolved together, and relationships developed that are mutually beneficial.
The short answer is, of course: If things had evolved differently and plants did not provide the nutrients needed for animal life.. we wouldn't be here asking this question (that's not to say, however, that intelligent life of some other form couldn't exist.)