Yes, Earth has water and its winter temperatures can be 0-15 degrees.
Not as a liquid but perhaps as Ice.
its the second planet away from the sun but surprisingly the hottest planet of them all no life form could survive on there it's temperatures can soar up to 500 degrees Celsius
No seasonal temperatures do not exist on Saturn. Saturn has a surface temperature that remains steady throughout the year at 178 degrees Celsius.
The most major issue is perhaps that there is no surface on which life can grow considering it is a gas planet, not a solid planet. Other issues arising from that include the lack of water on the planet and the presence of large storms in the atmosphere such as the Great Dark Spot. In addition, its distance from the sun makes it a very cold planet and hardly any life could exist that those temperatures.
A gas can exist in a wide range of temperatures, varying for each type of gas E.G. Water exists as a gas from 100 degrees Celsius to -
no
no
Steam can exist at various temperatures. Steam at a certain pressure can also exist at various temperatures.
Yes. Neptune is the outermost planet in the solar system.
Mercury certainly can exist in all three states. It freezes into a solid at -38.8 degrees C, and boils at 356.73 degrees C. In between those temperatures, it is a liquid.
Planet X does not exist - it was a hypothetical planet.
No, Planet X does not exist.