Q6 - The largest volcano on Mars

[perng.yan]

Could someone please post an explanation about this one too? I find it hard to distinguish between comparing Mars and Earth when they have differenet gravity... and then comparing their crust when they have simliar gravity... thanks.

[bbirdwell]

Here's what the second sentence says:

IF Earth's gravity were as low as Mars's, Earth still couldn't have a volcano that big, because the Earth's crust is too thin.

(A) is out of scope - erosion is not part of this.
(B) is unsupported - we don't know if this is true or not.
(C) is unsupported - we don't anything about the average height.
(D) is the answer. Earth's crust is too thin to support a volcano as big as the one on Mars. Therefore, we know that Mars's crust is thicker, at least in some places, than Earth's.
(E) is unsupported speculation.

[jionggangtu]

I am trying to figure out why E is wrong.

Is it because there are two conditions:

1) low gravity
2)the thickness of crust

E only mention if condiction 2) is matched, because 1) is not satisfied, we can not reach that conclusion?

would E be right, if it is like this: at least some of the Earth's volcanoes would be larger than they actually are if the Earth's crust were thicker than it is, and the gravity of Earth were as low as Mars'.?

[KakaJaja]

Hey Jionggangtu,

I think if both of the conditions are fulfilled, as mentioned in your post, the only conclusion we can get is "earth can support larger volcanoes", but the conditions allow existence doesn't necessarily mean that there will be larger volcanoes.

[wj097]

Hey Jionggangtu,

I think if both of the conditions are fulfilled, as mentioned in your post, the only conclusion we can get is "earth can support larger volcanoes", but the conditions allow existence doesn't necessarily mean that there will be larger volcanoes.

Though its really hard to say what can be true of hypotheticals, not sure if we can say "earth CAN support larger volcanoes" since we don't know other factors leading to larger volcanoes; there just might be other reasons that earth simply cannot support any volcano (though not true in real world sense). Just think about a situation where earth does not have layer x which might be crucial in supporting any mass of volcanoes. BTW the stimulus never mentions volcanoes exist in earth (just hypothetical on what might be possible).

[SecondWind180]

I am trying to figure out why E is wrong.

Is it because there are two conditions:

1) low gravity
2)the thickness of crust

E only mention if condiction 2) is matched, because 1) is not satisfied, we can not reach that conclusion?

would E be right, if it is like this: at least some of the Earth's volcanoes would be larger than they actually are if the Earth's crust were thicker than it is, and the gravity of Earth were as low as Mars'.?

I chose E as well. If E said "At least some of the Earth's volcanoes could be larger...." I think it would be a great answer because the use of "could" is allowing for the possibility. It must be true that is possible. However, the Makers used "would" which means it has to be and we don't know that for sure. So it's incorrect.

I misread and thought D was a 180 (the answer choice trap that gets me the most), so that's why I skipped over it.