Sure
There are planets in our solar system that have 100% liquid surfaces, why not water.
there is not water and oxygen
The Earth is sometimes called the "Blue Planet" or "Water Planet" because it is the only known planet that has large amounts of liquid water. Water bridges the gap to life, so water makes it possible for the Earth to support life.
Boats would be unnecessary on a planet without water. if the planet didn't have any water we would all die of dehydration.
yes, the planet Neptune includes water in all the gases on the planet, like methane, ammonia, helium and hydrogen.
yes. an ecosystem involves plants animals and water. earth is a big ecosystem and its a planet. so it is possible
underground
Yes.
Saturn is a gas planet, and if it were possible to place it in water it would float. Not sure if the rings would float, but, the planet itself would.
Yes, nuclear bombs can destroy most if not all human, animal, and plant life, and contaminate water supplies.
as of now no because there is no oxygen and no water ...maybe in the future though
Earth.
earth