More questions on human vs dog aggression?

First, Happy Thanksgiving Weekend to all the Canadian DSer's. Going off of this question - http://ca.answers.yahoo.com/question/index;_ylt=AhGxloHR1nxE1Ym7tArM59fAFQx.;_ylv=3?qid=20101004095500AAhZLkZ Maybe I am not understanding because I am not clear on what constitutes human aggression. What is... show more First, Happy Thanksgiving Weekend to all the Canadian DSer's.

Going off of this question -
http://ca.answers.yahoo.com/question/ind...

Maybe I am not understanding because I am not clear on what constitutes human aggression.

What is human aggression in a dog?

I have always believed that ANY dog will bite, given the right circumstances. The threshold at which point the dog will bite is the difference. Obviously biting out of pain is not human aggression.
At what point is a dog considered human aggressive? Or are they ever?
Is a dog aggressive dog a concern to bite a human?
Update: Please answer all questions, including dog aggression leading to human aggression.
Update 2: @Kate - you put any dog in the right situation and they will bite. All animals have the basic instinct to fight or flight. Take away the flight option and the dog will bite. It may be an extreme situation, but any dog will bite. Dogs bite because they were abused is complete BS. I know dogs that have been... show more @Kate - you put any dog in the right situation and they will bite. All animals have the basic instinct to fight or flight. Take away the flight option and the dog will bite. It may be an extreme situation, but any dog will bite.
Dogs bite because they were abused is complete BS.
I know dogs that have been raised since puppyhood, treated well and still bite.
Temperament is genetic.
Update 3: Read the question linked and answers. It may help to clarify what I am asking.
Update 4: Elaine - straining on the leash, growling and barking is not necessarily human aggression. It could very well be fear aggression.
I am not sure if I believe resource guarding is necessarily human aggression, even if they bite.
Update 5: No TDs are from me.

Just to clarify, this is not a breed specific question either.
Update 6: @ Curtis - I think I overstated the genetic thing. What I meant was saying that the ONLY reason a dog will bite was because it was abused is BS. @ Greek - I think the problem is I was looking at human aggression inthe non-trained form. I understand (somewhat) how training a dog to bite a human. I was more... show more @ Curtis - I think I overstated the genetic thing. What I meant was saying that the ONLY reason a dog will bite was because it was abused is BS.

@ Greek - I think the problem is I was looking at human aggression inthe non-trained form. I understand (somewhat) how training a dog to bite a human. I was more thinking of it in terms of your average dog becoming aggressive.

Thanks for the answers so far.
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