Q15 - The southern half of a

[rustyjkent]

I cannot figure out the difference between answer (E) and answer (D). Could someone please explain?

Thank you

[cyruswhittaker]

Choice E:

The passage states that during the Cretaceous period, which is part of the Mesozoic era, the southern half a certain region was entirely covered by water. We are also told that dinosaurs can live only on land.

Combining these two facts, it cannot be true that dinosaurs lived in the southern half of this region for the entire Mesozoic era because that would mean they would have lived in water. Thus (E) cannot be true.

Choice D:

The region that the passage discusses is only the southern half. We are given no information to infer anything about the northern half of the region. For example, by what is provided in the passage, it could be true that the northern half was not entirely covered by water. In this case, it could be true that dinosaurs inhabited this northern area. Thus, choice (D) is not necessarily false.

[ryangdollar]

D states that "Dinosaurs did not inhabit the northern half of the region during the Cretaceous Period". This could be true because all that we know from the stimulus is that Dinosaurs roamed the earth sometime during the Mesozoic Era. It could very well be that there were no Dinosaurs on Earth during the 75 million years of the Cretaceous Period but rather, they inhabited the earth during an earlier part of the Mesozoic Era.

[nmop_apisdn2]

The problem I have with this question is that it says, "The southern half of a certain region of the earth was covered entirely by water during the..."

Can you tell me exactly how this would mean that the entire southern half of the earth was covered in water, when the stimulus says that "half of a certain region?"

[ambrosiaserene]

The stimulus says that the southern half of a "certain region of the earth"....

As you said, this means just some region.

The answer choice E says dinosaurs inhabited the southern half of "the region" through out the entire Mesozoic era. I think "the region" here means the "certain region" in the stimulus, not southern half of the earth.

Therefore, E must be false since this region was filled with water during the last 75 million years of the M era. It cannot be true that dinosaurs live "in this region" through out the entire M era...at least not during the last 75 million years.

[syed_s_hus]

Hello everyone, I hope someone can help me with this problem. I picked A, and I do not understand how it could be wrong. By the way, I chose this answer because of the last statement. It seems to me like (A) contradicts the last statement, unless I misinterpreted the last statement.

[zee.brad]

I think the problem with answer A is "Dinosaurs inhabited". The only thing that we can learn from the last sentence is "No single species" "lived throughout", we don't know if it is the case that no dinosaur EVER inhabited, maybe species A inhabited for couple years, died and species B took over and lived for couple more years and so on. So A could be true in that sense. However, answers choice E is certainly wrong because dinosaurs cannot live in water whats so ever. Hope that make some sense.

[rinagoldfield]

Great conversation!

The four wrong answer choices on this inference question could be true; we’re looking for the one that must be false.

Zee.Brad, great assessment of (A). We know that no individual species of dinosaur survived the entire Mesozoic Era, but dinosaurs in general could have hung around the whole time. For example, it could be true that T-Rexes lived at the beginning of the Mesozoic era, and then stegosauruses came around.

No one on this thread has had an issue with (B), but I’ll rule it out: plesiosaurs could have lived in other aquatic areas.

(C) not only could be true_ it must be true. Plesiosaurs lived exclusively during the Cretaceous period. They definitely didn’t inhabit the "southern half of the region" _or any other region_ prior to that period.

Cyrus’s takedown of (D) is perfect:

The region that the passage discusses is only the southern half. We are given no information to infer anything about the northern half of the region. For example, by what is provided in the passage, it could be true that the northern half was not entirely covered by water. In this case, it could be true that dinosaurs inhabited this northern area. Thus, choice (D) is not necessarily false.

(E) on the other hand, absolutely must be false. We know that the southern region was entirely covered by water, and dinosaurs can’t live in water.

[hyk1310]

Rina, if I may, I think there is a flaw in the explanation that you have supported.

There is no information about the northern region, but the important thing is that answer choice D says Dinosaurs DID NOT inhabit the northern region.

It's not that dinosaurs could've lived in the northern region. Rather, alternative explanation may be that that dinosaurs didn't live during the Cretaceous period.

[jiexic67]

Here's my thought in tackling this Must Be False question.

We can deduct a Must Be True inference from the argument alone: Since the southern half of the region was covered entirely by water in Cretaceous, and dinosaurs lived only on land,thus it's must be true that dinosaurs didn't live in the southern half of the region in Cretaceous.

Any answers destroy this inference will be the correct answer.

(A) (D) : We know nothing about if dinosaurs in general lived in northern half of the region, thus they all could be true.

(B)(C): The only thing concerning Plesiosaurs we feel confident about is that they only lived in Cretaceous. we don't know where did they live.

(E): Mesozoic includes Cretaceous, exactly the answer I am searching for.

In sum, i feel like to answer Must be true/Could be true/Must be false questions , one strategy is to actively seek in the argument for any solid (must be true) conclusions, if any. Then in Could be true question stem type, we just eliminate the answers that destroy our inference; in Must be false question,just do the opposite.