The correct answer is OD. Strong gravity.
Here's why:
1. Gravity is the force that pulls objects towards the center of the Earth. It is this strong gravitational force that keeps bodies of water, such as oceans and lakes, from floating off into space. Without strong gravity, water bodies would not be able to stay on Earth's surface.
2. The Earth's gravity is essential for maintaining the balance of water on our planet. It prevents water from evaporating into space and helps to shape the landscape through erosion and deposition processes.
3. The other options provided in the question do not directly contribute to Earth's ability to maintain bodies of water. Lunar tides are caused by the gravitational pull of the Moon, plate movements are related to the Earth's crust shifting, and the strong magnetic field of Earth is important for protecting the planet from solar wind but does not play a direct role in maintaining bodies of water.
In conclusion, the strong gravity of Earth is the primary factor that allows it to maintain bodies of water on its surface.
