Self-study
In the troposphere, the lowest level of the earth's atmosphere, the temperature decreases as one progresses straight upward. ██ ███ ████ ███ ███ ███████████ ██████ ████ █████ ███████ ███████ ████ ███ █████ ██ █████ ███████ ███████ ████ ███ ████████ ██ ████ █████ ███ ████████████ ███████ ███ ███ ███████████ █████ ██████████ ███ ███████ █████████ ██ ███ ██████████ ████████ ██████ ███████ ███ █████████████ ███ ████████████ ██ ██████ ██ ██████ ████ ██ █████ ████████ ███████ █ ████ ██ ███████████ █████████ ████ ██ ██████████
Summary
The stimulus discusses two layers of the atmosphere: the troposphere (the lowest level) and the stratosphere (the layer above the troposphere).
In the troposphere, it gets colder as you go straight up.
At the top of the troposphere, the temperature ranges from -50 degrees Celsius (over the poles) to -85 degrees Celsius (over the equator).
Once the stratosphere begins, temperature beings to increase as you go straight up.
In the stratosphere, heat is generated when an ozone particle absorbs ultraviolet sunlight.
Notable Valid Inferences
Any point in the troposphere is colder than any other point in the troposphere directly below it.
Any point in the stratosphere is warmer than any other point in the stratosphere directly below it.
A point in the stratosphere is equal temperature or warmer than the highest point in the troposphere directly below it.
18.
If the statements above are █████ █████ ███ ██ ███ █████████ ████ ████ ██ █████
a
The troposphere over ███ █████ ██ ███████ ████ ███ ███████████ ████ ███ ████████
This could be false. We don’t know anything about the thickness of any layers of the atmosphere.
b
It is warmer ██ ███ ███ ██ ███ ████████████ ████ ███ █████ ████ ██ ██ ██ ███ ███ ██ ███ ████████████ ████ ███ ████████
This could be false. We don’t know anything about the rate of temperature increase in the stratosphere; it could be the case that the temperature over the equator increases more quickly than the temperature above the poles.
c
The temperature in ███ ██████ ████ ██ ███ ████████████ ████ ███ █████ ████ ██ ██ █████ ██ █████ ██ ███ ███████████ ██ ███ ██████ ████ ██ ███ ████████████ ████ ███ ████████
This could be false. We only know the temperature at the point where the troposphere ends and the stratosphere begins; we don’t have enough information to compare points in the middle of the stratosphere.
d
The temperature at ███ █████ ██ ███ ███ ██ ███ ████████████ ██ ██ █████ ██ █████ ██ ███ ███████████ ██ ███ ███ ██ ███ ███████████ ████████ ███████ ████ ██████
This must be true. We know that, in the stratosphere, the temperature increases as you go straight up. Because of this, we can infer that any point in the stratosphere is at least as high as the point below it, going all the way down to the highest point of the troposphere.
e
Depletion of the ███████ █████ █████ █████ ████████ ███ ███ ███████████ ██ ███ ████████████ ███ ████████ ███ ███ ███████████ ██ ███ ████████████
This could be false. All we know about ozone is that it plays a role in warming the stratosphere; we have no reason to believe that removing something that generates warmth would cause the stratosphere to become warmer.