Why did comets form in the Kuiper belt and not in the asteroid belt

Asteroids lie in the asteroid belt and comets lie in the Kuiper belt beyond the orbit of Neptune. The composition of asteroids and comets is different.

Comets are composed of rocks, dust, ice and frozen gases. These are thought to be formed from the debris of the solar system.

On the other hand, asteroids are irregular shape and size rocky bodies lying between the orbit of Mars and Jupiter. There are thought be remnants of a planet which could not form.

Comets formed in the Kuiper belt because of very low temperature and what they are composed of.

The kuiper belt is colder so water vapor can turn in to ice but the the astoriod belt it is hotter