Question

The atmosphere is held to the earth by:
A. gravity
B. wind
C. clouds
D. earth’s magnetic field

Answer 1

As the particle which has mass will have gravity acting downward. So, is the care here for the atmosphere to be held.

Complete step by step answer:
We know that according to universal law of gravitation, each and every object in this universe attracts every other object with a force of gravitation which is directly proportional to the product of masses and inverter sly proportional to the square of distance between them i.e.

Force of gravitation, $F = \dfrac{{GMm}}{{{r^2}}}$
Where G is the universal graduation constant M and m are the masses of two objects and r is the distance between them.
Now, our atmosphere consists of various gases like nitrogen, oxygen, carbon dioxide and many others.
These gases have mass and thus there exists a gravitational force between earth and these gases. These forces hold the various gases near the surface and thus atmosphere is present.
Earth’s gravity helps in keeping the atmosphere on earth.
Hence, option (B) is correct.
Additional Information: One of the concepts of the atmosphere's existence on earth, not on other planet’s is that the escape velocity of earth is much higher than that of gases. So, they can escape the earth’s atmosphere which depends on the acceleration due to gravity, g white that of other planets, this escape velocity is less that of the gases.

Note: The attractive or gravitational four in case of earth is the weight which is mg i.e. mass x gravity. So, it depends on gravity.