Because on most planets (mars being an exeption as there are places where water can stay liquid) temperature and/or atmospheric pressure is to high or low for water to stay liquid.
The earth is in what astronomers call the 'Goldylocks Zone': Just the right distance from our sun that liquid water can exist.
earth
huge
Earth.The Earth is about 70% covered with water. We can't be too sure about other planets, although Mars and Mercury are certainly dry, and Venus is too hot for water to remain liquid.
The Sun is not a planet. It is a star. The Earth has gas on it, but it is not gaseous compared to the planets defined as gaseous. So your answer would be no the Sun and the Earth are not gaseous planets.
3rd
Because of Earth's size, and considering it as one of the smallest planets, it has a weak gravity compared to the OTHER planets. Most planets have greater gravity because of their size. Earth has a stronger gravity compared to mars, mercury, and venus.
http://solarsystem.NASA.gov/planets/compchart.cfm
Earth is the only known planet with liquid water.
no, not compared to other planets around us. Think about it.
Earth!
Earth is more of an oval compared to all the other planets.