Some mountains in island, country, Earth. Mountains are parts of the earth's crust that are higher than the surrounding area. Mountains usually have steep sides that significantly expose the bedrock. Mountains differ from plateaus in that they have a limited summit area; a mountain is larger than a hill, usually having a height of at least 300 meters (1,000 ft) above the surrounding land. Some mountains are stand-alone peaks but most are part of mountain ranges.
The sea is a large and extensive collection of salt water that inundates and divides land into continents or islands. So the sea is water that covers a very large land surface and generally contains salt and tastes salty.