The Asteroid Belt...what's it's purpose?

Got all this from wikipedia...... The asteroid belt is a region of the solar system falling roughly between the planets Mars and Jupiter where the greatest concentration of asteroid orbits can be found. It is termed the main belt when contrasted with other concentrations of minor planets, since these may also be termed asteroid belts. In this usage, it often refers only to the greatest concentration of bodies with semi-major axes between the 4:1 and 2:1 Kirkwood gaps at 2.06 and 3.27 AU, with eccentricities less than about 0.33, and with inclinations below about 20°. This region is marked in red in the diagrams below, and contains approximately 93.4% of all numbered minor planets. The asteroid belt region of space also contains some main-belt comets which may have been the source of Earth's water. Am presently unable to put a pic up....and need to add another post up.... cheers.

The general concensus of opinion is that the asteroid belt is simply the remains of a previous planetoid mass that broke up either due to instability or from the impact of another body, but of course you already knew that. I have no reason to doubt the theory as it is perfectly logical and I cannot see any realistic alternative explanation.