Well Balto was the fast one and even though they thought he
could turn on them they were desperit. This is the real life
one. They also my of known he was part wolf so he would
navigate a little better then the others. In the moive he
gose on his own to help. He did on his own. No one choose
him.

Well, I think I see what you're asking. Unless I'm
mistaken, it appears you've been asking about the REAL
Balto. If you DO mean him, he was actually a purebred husky
of the Siberian stock (from the Chukchi Inuits of Siberia).
He was born, owned and raised in the kennels of legendary
Norwegian racer, musher, husky breeder and Pioneer Gold
Mining Company employee Leonhard Seppala. HE never was a
stray.

If, however, you're referring to the
cartoon Balto, I'd suggest you buy or rent the Balto movie,
and watch it. You'll soon have all your answers.

I'm guessing that they were desparate and take any chance
they could to get the medicine. He wasn't exactly chosen, he
just knew that the team was lost so he decided to help them.
That was his own decision.

If you're referring
to after the race, that was simply because he was the
fastest dog and they needed a fast dog to get the medicine.