True
It is supposed to be an "average" comet, but there is much speculation as to whether or not this is true. The mass of the object is still in question, and that helps promote the idea that it may not be a comet.
True. The tail of a comet extends away from the Sun due to solar wind pushing the comet's dust and gases away from the nucleus.
No, Edmund Halley was not the discoverer of Halley's comet. He predicted the return of the comet, which led to its recognition as a periodic comet and its eventual naming after him. The comet's true discoverer is unknown, as it has been observed and recorded by various cultures throughout history.
No, it's not (Halley's is a periodic comet, but its period is shorter than that, by about ten years).
a comet/meteorite
I think that he is often associated with Halley's Comet because he was born during a visit from the comet and he predicted that he would "go out with it" as well. As predicted, he died the day following the comet's subsequent return.
Mark Twain was born in 1835, the year when Halley's Comet made its closest approach to Earth. Twain famously predicted that he would not die until the next return of the comet. True to his prediction, Twain died in 1910, the year after Halley's Comet's next return.
It is a comet.
I doubt that the earth will be destroied by a comet in 2010. The earth was suppose to end and get destroied back in 2001 but that never happened. What makes this time so different? I wouldn't worry about it.
Halley's Comet
The comet's tail is in front of the comet, not after