When they approach so close tot he Sun that some of their matte stars to break off (melt) out around the asteroid belt I would guess.
Why do comets have tails
No, they do not burn only comets have tails.
No, that would be comets.
yes
Comets
rocks and dust
It depends on how fast the comet is going.
When they reach the inner solar system.
In the sense that an observer can see tails on comets - no, the gravity and composition of Mars is not favorable to the production of a tail.
yes
They are called comets.
Comets