Answer:
4,801 alien planets are known till now.
The right answer is oceans of course.
Hope it helps.
C. The study of unique traits of different parts of the world
Surface of the Earth: Most of the Earth's surface (70%) is covered with water, and the remaining 30% is taken up by the seven continental landmasses. However, underneath the water that fills the oceans, and the dirt and plants that cover the continents, the Earth's surface layer is made of rock.
