The solar wind (energetic particles from the Sun) blows them off the nucleus, or comet body. If seeing is good, there are usually two tails, a gas tail and a dust tail.
Why do comets have tails
No, they do not burn only comets have tails.
No, that would be comets.
yes
They won't change form, but willslowly thaw and disperse: their tails are of material streaming from their surfaces as they approach the Sun.
Comets
Tails, not trials. They're called comets, and their "tails" form when the comet gets near the sun, vaporizing away some of the ice.
rocks and dust
No, solar flares do not give comets their tails. The tail of a comet forms from the solar wind interacting with the comet's nucleus, causing gas and dust to be released and form a tail that points away from the Sun. Solar flares are bursts of energy from the Sun's surface and are not directly responsible for creating comet tails.
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.