Protein expression can be modulated by chemical gradients, and differing expression patterns will alter behavior. This gives you changes in behavior in response to external stimulus. Protein expression patterns are heritable, and therefore open to selection.
To quote a friend of mine, because dead things don’t breed.
Gravity also invokes a direction. Asked and answered.
There clearly isn’t, because selective disadvantage is measurable and there isn’t one for humans not making those amino acids. But thank you for demonstrating you don’t understand the words you are using.
Because vitamin C is extremely common in the human diet.
Then you don’t understand selective benefit.
The GULO gene is demonstrably broken. If you reject this, you are wrong. If your YEC ideology demands this be rejected, then YEC is wrong. Thanks for playing.
It’s not that we ‘must’, it’s just that we do because it’s clearly true.
You’ve admitted that you believe that humans and primates are related, you just think it is by design rather than descent. It makes no difference, they are still related, they still all have a broken gene, broken in the same way. Still a problem for you, and not for me.
If it is your understanding that I believe that humans and other apes are related because neither can make vitamin C or certain amino acids, you are wrong. These things are consistent with common descent, but I believe humans are apes from the parsimony of a broad collection of fields.
In the future, you may want to confirm the ‘since’ in your question before asking the question based on it.
Wrong.
The absence of a selective disadvantage isn’t a matter of opinion. It is clearly true.
The novel proteins are new, so not existing variation.
You mean from getting hit, or an actual protrusion of bone? Because the former would not be a new structure, while the latter would. And the frequencies of the alleles responsible would be examples of evolution.