In the troposphere, the lowest level of the earth’s atmosphere, the

In the troposphere, the lowest level of the earth’s atmosphere, the temperature decreases as one progresses straight upward. At the top, the air temperature ranges from -50 degrees Celsius over the poles to -85 degrees Celsius over the equator. At that point the stratosphere begins, and the temperature stops decreasing and instead increases as one progresses straight upward through the stratosphere. The stratosphere is warmed by ozone. When an ozone particle absorbs a dose of ultraviolet sunlight, heat is generated.

If the statements above are true, which one of the following must also be true?

(A) The troposphere over the poles is thicker than the troposphere over the equator
Incorrect. Out of Scope. we don't have sufficient information about the thickness of the troposphere and how it affects the temperature

(B) It is warmer at the top of the stratosphere over the poles than it is at the top of the stratosphere over the equator
Incorrect. We cant relate between the temperature over poles and over the equator for the stratosphere.

(C) The temperature in the middle part of the stratosphere over the North Pole is at least as great as the temperature in the middle part of the stratosphere over the equator
Incorrect. Again Lack of information

(D) The temperature at any point at the top of the stratosphere is at least as great as the temperature at the top of the troposphere directly beneath that point
Correct. Yes we can infer that how the temperature decreases till the top of the troposphere, where the stratosphere begins and increases through the stratosphere.

(E) Depletion of the earth’s ozone layer would increase the air temperature in the stratosphere and decrease the air temperature in the troposphere
Incorrect. This 180 degree, Actually result would be opposite of that

Hey nightblade354

Please help in explaining this one.

Thanks!

In the troposphere, the lowest level of the earth’s atmosphere, the temperature decreases as one progresses straight upward. At the top, the air temperature ranges from -50 degrees Celsius over the poles to -85 degrees Celsius over the equator. At that point the stratosphere begins, and the temperature stops decreasing and instead increases as one progresses straight upward through the stratosphere. The stratosphere is warmed by ozone. When an ozone particle absorbs a dose of ultraviolet sunlight, heat is generated.

If the statements above are true, which one of the following must also be true?

OK, so this is an inference question, which means the answer has to be 100% true, and 100% provided in the stimulus above!

(A) The troposphere over the poles is thicker than the troposphere over the equator -- Where does it talk about thickness in the stimulus? We are told about pressure and temperature, so this is incorrect

(B) It is warmer at the top of the stratosphere over the poles than it is at the top of the stratosphere over the equator -- Our stimulus talks about the Troposphere's temperature, but we do not know anything about the stratosphere's temperatures over those points. Therefore, this is incorrect

(C) The temperature in the middle part of the stratosphere over the North Pole is at least as great as the temperature in the middle part of the stratosphere over the equator -- Again, same as B, we are never told anything about the temperature of the Stratosphere over certain areas

(D) The temperature at any point at the top of the stratosphere is at least as great as the temperature at the top of the troposphere directly beneath that point -- This is our answer. As the stimulus says: the Stratosphere will always be warmer than the top of the Troposphere because it starts warming as soon as it changes from the stratosphere to troposphere. And since the top of the stratosphere is its coldest point, this will always hold true

(E) Depletion of the earth’s ozone layer would increase the air temperature in the stratosphere and decrease the air temperature in the troposphere --OK, this one is just for laughs. No where is depletion mentioned. See, even the LSAT wants to give you one every now and again to laugh at. They are trying to get you to use outside knowledge for a question that has given you all of the information you need. This is done often, so you must be aware not to bring personal views into inference questions

Thanks nightblade354
This helps!

hi, i think you have provided inverse relation.
in stimulus it is given that tropo has "decreasing temperatures, i.e colder " ,while strato gets warmers wrt to height in strato.
you have mentioned the reverse. please check and correct me if i'm wrong

AdityaHongunti,

Yup, I had them reversed in my explanation. Good catch.

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