Gravity
Gravity, easy!
Gravity
the gravitational force holds its atmosphere together
calamities
Gravity keeps water on Earth. Note that if you consider water is just the liquid substance, this seems obvious, but if you consider it is also a gas (water vapour), which can move away from the surface of the Earth with the air , then it isn't so obvious. Nonetheless, water vapour, the molecule H2O, is still too heavy to escape the Earth's gravitational pull. As a contrast, consider Mars or the Moon, where water will not stay on the surface, and escapes into space, such that there is none left on those bodies. Other gases do escape, such as hydrogren or helium.
gravity
Gravity, easy!
Gravitational force formed the earth and holds all things on its surface - including us!
The gravitational force between the Earth and the atmosphere holds the atmosphere close, just like it holds you close to the Earth. (ground)
It's the mutual forces of gravitational attraction between the Earth and each object.
At the surface, it is 2.64 times its value at the Earth's surface.
Gravity
The mutual force of gravitational attraction between the sun and the earth.
The air is close to the surface of the earth because gravity holds it there
the gravitational force holds its atmosphere together
Gravity.
Gravity.