The answer is letter A. meteorite bombardment.
During the Earth's earliest beginning, it went through a period of catastrophic and intense formation. By 3-8- 4.1 billion years ago, Earth's atmosphere was never the same as today. This is because of its formation during the pre-Cambrian period whereby t<span>he Earth formed under so much heat and pressure that it formed as a
molten planet.
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Earth was bombarded continuously by the remnants
of the dust and debris — like asteroids, meteors and comets — until it formed
into a solid sphere, pulled into orbit around the sun and began to cool down during the Hellish period (4.5 to 3.8 billion years ago).
<span> </span>.To know more of this topic, see attached file.
5 meteals that are more useful for electroplating carbon,seth,
The work done to pull the sled up to the hill is given by

where
F is the intensity of the force
d is the distance where the force is applied.
In our problem, the work done is

and the distance through which the force is applied is

, so we can calculate the average force by re-arranging the previous equation and by using these data:
Mass is measured in kg
Velocity is measured in ms^-1
Hope this is what you were looking for
Acceleration = Change in velocity / time taken
= (5 - 15) / 2
= -5 ms^-2