No, it can't.
a king snake
NO. It is physically impossible for a human to give birth to a snake
It depends on your snake.
Voldemort didn't change his appearance voluntarily, he changed because he had made so many Horcruxes he wasn't really human any more and resembled a snake (he also made a snake into a Horcrux).
a snake because it has venom
He is a snake in the form of a human.
no
No.
Snakes don't have "snake years". A snake's age is the same in human years.
No, a snake's age is the same in human years.
If the snake is big enough it will just unhinge its jaws
no