because it is a planet
None of the planets are stars, only the stars. See related questions.
Galaxies are generally a collection of stars. But within any galaxy, there are lots of other objects, including planets. So galaxies are related to planets in some ways.
No, planets are not stars. Stars are huge balls of burning gas, planets are not. At certain times, there are 5 planets that are visible with the naked eye in the night sky. Some of these are similar to stars but much closer. They are Mercury, Venus, Mars, Jupiter and Saturn. See the related link for more information.
Planets orbit stars.
stars, the planets have to get heat from stars
Stars The 2006 German poster is in the "Related Links" section
No. Supernovas are cataclysmic eruptions from massive stars that have come to the end of their lives. See related questions
Planets do not technically need their respective stars, but stars keep planets in orbit and provide heat and light to the planets.
Polaris is a star. It is likely that it has planets, i.e. that there is a related solar system, since most stars seem to have planets.
On the contrary! A star has planets, which circulate it. And planets have moons. Stars do not circle planets.
Planets and stars have gravity.
The term planet came from greek astronomers. They called wandering stars asteres planetai. They called the fixed stars asteres aplanis. See the related link for more information.