What will we eat?

I attended social psychology class - Which asked a question - "we think killing humans is wrong but we eat animals. Are you discriminating against animals?" 

[Got me thinking  isnt that question discriminating against plants? They care for animals ok but plants are alive too. Do plants deserve rights as well?  Do plants have emotions, Do they feel? 
I feel very sad when I see a tree being cut, but I dont feel all that bad when I eat chicken that afternoon.  So... when I saw a course on coursera - What plant knows? I want to know what plant knows.]

https://secure.einterview.org/lifestyle/

The questions in the interview are the ones I ask myself many times.The interview  provokes introspection which is very good, but the questions are pointed, trying to push their thinking in a certain way - which is not good. Some how puts ideas in our head and may promote biased self introspection? I wonder. Are there flaws in their thinking?

Two arguments came to my mind.
1) Death is part of life. Nature produces in excess so that the weak are weeded out and the fittest survive. Evolution happened because infant mortality in nature is very very high. Is it really wrong to kill animals.  

2) Where does the line of "compassion"  start? When do species start qualifying for compassion? 
Animals are alive, people are alive, plants are alive, like someone else said on the thread insects fungii and bacteria are also alive. Does small pox virus not have a right to live? and polio?  where to draw the line?  
Some Buddhist monks do not kill mosquitoes who bite them. Jain people dont eat potatoes and ginger. Each person draws his own line, mine is humans/pets/wild animals are this side of the line and farm animals on the other side.

There is a saying Cow cant be friends with grass...  
If we dont want to eat anything then we would have to have chlorophyll in our skin and make our own food, once we start doing that there wont be any need for us to move or get around so we will grow roots and turn into plants and new life forms which will eat us will evolve :-) :-)

but still it is a moral dilemma ,I feel if we give back as much as we take from nature.. may be thats the solution. 
[from discussion forums on coursera ]