Answer:
c. natural force or pull toward the earth
Explanation:
Gravity of the earth is the force of attraction that it naturally possesses to attract any mass.
An apple falls on the earth due to this force of gravity.
The force of gravity near to the surface of the earth is given as:
where:
m= mass of the body
g= acceleration due to gravity
The variation of the gravitational force with height is given as:

where:

where
R = radius of the earth 
A discovery not the others
Answer:
You are exactly right. The molecules in hot air are moving faster than the molecules in cold air. Because of this, the molecules in hot air tend to be further apart on average, giving hot air a lower density. That means, for the same volume of air, hot air has fewer molecules and so it weighs less
The Earth orbits the sun constantly, continuously, and all the time. " 24/7/365 "
From the sun's point of view, it takes the Earth roughly 365 and 1/4 days
to make the complete trip, all the way around one time. That's the length
of time that we call "one year".
When you talk about orbiting in one month, you're thinking of the moon
orbiting the Earth. THAT length of time is about 27.32 days.
KE = (1/2)·(mass)·(speed)²
It doesn't matter whether the object is in a car, on a boat,
falling, on a conveyor belt, or being carried by ants.
KE = (1/2)·(40 kg)·(2 m/s)²
KE = (20 kg)·(4 m²/s²)
KE = 80 kg-m²/s²
KE = 80 Joules