We want to predict what will happen to the density of the air on the surface of the Earth when it warms up.
We will see that the correct option is D: "It decreases, then increases"
We know that the temperature of a given object (in this case a mass of air) is related to the kinetic energy of the particles that conform it.
As the temperature increases, the kinetic energy also increases, thus, the amount of motion of each particle increases, thus, the volume of the object increases.
Now remember that:
density = Mass/Volume.
So if the volume of something increases, we will see that the density decreases (as the volume is in the denominator).
Then if the temperature of the air increases, we will see that the density of the air in the surface decreases.
But it does not end there, as only the air near the surface suffers this change of density, we will have a denser mass of air (colder air) above it. And because it is denser (has more mass in the same volume) we can say that it is heavier.
Then eventually the hot air will rise, and the cold air will fall down, thus the density of the air in the surface increases again, as the colder and denser air comes near the surface.
This is one way of how wind currents are born.
Concluding we can see that the correct option is D: "It decreases, then increases"
If you want to learn more, you can read:
https://brainly.com/question/14482731
