Planet, planetoid, moon, asteroid, meteor, comet
Moon, asteroid, planetoid...
Planetoid
No. Sedna is currently classified as a planetoid.
No. For one thing, Halley's comet is a comet, not an asteroid. The largest asteroid is Ceres, which is far larger than Halley's comet.
A planetoid - a.k.a. an "asteroid" - is basically a small planet.
Planetoid is another name for an asteroid. See the related link for more information.
no
Scientists usually refer to this as an asteroid, not a comet. It's the asteroid that caused the Chicxulub crater.
Comet
the asteroid belt is safe for now long as there ere rouge comets comet comet clos to the belt
9P/Tempel or Tempel 1 is a comet, not an asteroid.