The more sunlight our planet reflects back into space, the cooler the global atmosphere tends to become. Snow and ice...

Ravi on May 23, 2019

@wills,

Happy to help. We're looking to strengthen the argument in the stimulus.

This argument says that the more sunlight our planet reflects, the
cooler the atmosphere will become. Snow and ice reflect more sunlight
than water or land, so the more our planet is covered by snow and ice,
the cooler our planet's atmosphere will become.

This makes sense, but in order to make it better, it would help to
know what happens when the sun's light shines on ocean water and land
that doesn't have any snow or ice cover. We know from the stimulus
that snow and ice help a lot for cooling the planet's atmosphere, but
if we had additional information that told us that ocean water and
land that doesn't have snow or ice over it contributes to making the
atmosphere warmer, that'd strengthen this argument even more. The
reason this would strengthen the argument more is that we'd then know
that in covering up things that make the atmosphere warmer (ocean
water and land) with things that make the atmosphere cooler (snow and
ice), it would seem much more likely that more of Earth's are covered
by snow and ice would result in a cooler atmosphere.

(C) says, "Ocean water and land heated by sunlight in turn warm
Earth's atmosphere."

(C) does an excellent job in strengthening the part of the
relationship with ocean water and land (and snow and ice) that we
discussed above. With (C), we know that ocean water and land
contribute to a warmer atmosphere, so if more ocean water and land
were covered with snow and ice, then it would be far more likely to
create a cooling effect on Earth's atmosphere. Thus, (C) strengthens
the argument and is the correct answer choice.

Does this make sense? Let us know if you have any more questions!

Kanyin on July 1, 2019

Could you expand on why E is wrong?

Ravi on July 1, 2019

@Kanyin,

(E) says, "Lighter-colored soil reflects more sunlight back into space
than does darker-colored soil."

Remember, we're looking to add something to strengthen the argument.
(E) simply tells us that different types of soil (land) reflect
sunlight at varying rates. However, we have no clue which type of soil
covers most of the land on Earth, so (E) does not provide us with
enough new information to strengthen the argument. It's too vague, so
it's incorrect.

Does this make sense? Let us know if you have any other questions!

Minerva on September 2, 2019

Why is D wrong?

shunhe on December 22, 2019

Hi @Minerva,

(D) is incorrect because the conclusion in the question takes about cooling the atmosphere, whereas (D) takes about how the atmosphere is warmed. It also doesn't talk about reflection of heat. Hope this helps.

Sheza on August 24, 2020

Hi @shunhe - but by that same logic, C should be wrong as well since it talks about warming the atmosphere. Could you clarify how talking about ocean water and land strengthen an argument made about snow and ice? Thank you