You can see asteroids in the sky.
Technically yes. [See related question] However, there are no known asteroids classified as planets. The closest would be Ceres, a dwarf planet. [See related question]
Well at the moment, we don't know. But the reason we don't often see asteroids around earth, is because Jupiter is help us by sucking in most of the asteroids.
Usually comets are icy as that is why you see the icy trail, but asteroids can be icy too.
asteroids and comets!
The Mercury, Venus, Earth and Mars have many asteroids - they are contained in a belt called the Apollo Asteroids [See related question]
No the sun does not have asteroids because by the time the asteroid got away from the sun there would be nothing left of it.
Mainly to see if the asteroids are going to pose a collision danger with regards to the Earth.
No, the total mass of all the asteroids in the asteroid belt is estimated to be less than 4% of the mass of the Moon. Even if all the asteroids were combined, they would still be much smaller than the Moon.
They are relatively small and far away.
Sometimes. We call them "asteroids" when we see them floating in space. Occasionally, one of them (or a piece of one) will collide with the Earth's atmosphere, and it will burn up as a meteor.
Between mars and Jupiter
The Sun; planets; moons; dwarf planets; asteroids; meteoroids; interplanetary dust and gas; comets; solar wind...