Archaeologist: The latest discovery at the dig site at Water Creek is

Question

Archaeologist: The latest discovery at the dig site at Water Creek is a large bone. The bone appears to be the tibia, or shin bone, of a hominid species. Because of the condition of the soil and extensive contamination, radiometric dating has been able to place the bone's age within a range of 1.5 and 2 million years. However, the bone shows signs of damage associated with the mammoth plague, which ran rampant in this part of the world from 1.9 to 2 million years ago. Thus, we can further pinpoint the age of the bone within a range of one hundred thousand years.

Which of the following, if true, casts the most doubt on the archaeologist's suggested range of the age of the bone?

A. Most other animal fossils uncovered in the area surrounding the dig site have been found by carbon-dating to be more than 2 million years old.
B. The mammoth plague killed mammoths and other large animals but not hominids.
C. Ample archaeological evidence exists to support the hypothesis that the last outbreak of mammoth plague occurred 1.9 million years ago.
D. Fossils from the area that are between 1.5 and 1.8 million years old provide evidence of the mammoth plague.
E. Fossils from the area that are more than 2 million years old provide evidence of the mammoth plague.

arora1 · Answer

Archaeologist: The latest discovery at the dig site at Water Creek is a large bone. The bone appears to be the tibia, or shin bone, of a hominid species. Because of the condition of the soil and extensive contamination, radiometric dating has been able to place the bone's age within a range of 1.5 and 2 million years. However, the bone shows signs of damage associated with the mammoth plague, which ran rampant in this part of the world from 1.9 to 2 million years ago. Thus, we can further pinpoint the age of the bone within a range of one hundred thousand years.

Radiometric dating : bone's age 1.5 and 2 million years 
Bone signs : bone's age 1.9 and 2 million years
Conclusion: Bone has a range of 1.9 to 2 million years old

But what if multiple plagues (and not just one) took place between 1.5 and 2 million years ago?  - This can be a weakener

Which of the following, if true, casts the most doubt on the archaeologist's suggested range of the age of the bone?

a. Most other animal fossils uncovered in the area surrounding the dig site have been found by carbon-dating to be more than 2 million years old. Other animal fossils? unrelated. We are concerned about that particular bone 
b. The mammoth plague killed mammoths and other large animals but not hominids.  This can be a close option, but the argument says damage. Even if the mommonths were not killed, thier boned could have been damaged. Thus, if bones show signs of plague, bones can be dated suitably. Thus not a weakener 
c. Ample archaeological evidence exists to support the hypothesis that the last outbreak of mammoth plague occurred 1.9 million years ago. Author is agreeing to this fact. Thi does not weaken the conclusion 
d. Fossils from the area that are between 1.5 and 1.8 million years old provide evidence of the mammoth plague.
e. Fossils from the area that are more than 2 million years old provide evidence of the mammoth plague. More than 2 million has no effect on the conclusion. We need something between 1.5 and 2 years. Just as option D states, if the plague happened between 1.5 and 1.8 million years ago also, the it is unlikely that bone is from a hominid that existed 1.9 to 2 million years ago

peace31 · Answer

Archaeologist: The latest discovery at the dig site at Water Creek is a large bone. The bone appears to be the tibia, or shin bone, of a hominid species. Because of the condition of the soil and extensive contamination, radiometric dating has been able to place the bone's age within a range of 1.5 and 2 million years. However, the bone shows signs of damage associated with the mammoth plague, which ran rampant in this part of the world from 1.9 to 2 million years ago. Thus, we can further pinpoint the age of the bone within a range of one hundred thousand years.

Radiometric method  gave an estimate between 1.5 and 2 million years
 Mammoth plague  understanding gave an estimate between 1.9 and 2 million years
 Conclusion:  Considering the common duration, bone has an age range of 1.9 to 2 million years. (hundred thousand years)

Weakener: Find the answer choice which takes the final estimate away from 1.9 to 2 million years.

I am sure most of the students choose between Options B, D, E.

B. The mammoth plague killed mammoths and other large animals but not hominids. 
 This is talking about killing where as we need data about damaging. It could be just a subtle plague which doesn't cause death. Out of scope.

D. Fossils from the area that are between 1.5 and 1.8 million years old provide evidence of the mammoth plague.
 This option has atleast a hundred thousand years difference wrt conclusion. So far the best answer.

E. Fossils from the area that are more than 2 million years old provide evidence of the mammoth plague.
 This option has less than hundred thousand years diffrence wrt conclusion. Not the best answer.

dharam44 · Answer

Please explain why E is not correct ?
 GMATNinja 
 souvik101990

gauranggarg · Answer

dharam44  Even I am not 100% sure. Only reason I can think of is that the radiometric dating age was between 1.5 and 2. So we do not need to worry about anything over 2 M.Y.

Posted from my mobile device

dharam44 · Answer

thanks for your response 
 gauranggarg

mbagizmo · Answer

dharam44  The conclusion is that we can estimate the range within 100 thousand years (1.9mn to 2mn). However, older than 2mn can also mean 2.05 mn. That still lets us assume the same 100 thousand years range. However, if the plague happened between 1.5 and 1.8mn years, then there is definite chance of the range being more than 100 thousand years.

dharam44 · Answer

thanks a lot! I get the point.

popcornninja

abhimba24 · Answer

For E, can we give this reason?

--> 2+ age not surely increases range. It can either be 2.00001 or 2.987.. Does that makes sense?

MacT750 · Answer

But passage talks about mammoth plague in particular are and option d talks about a area where mammoth plague happened 1.5 to 1.8 million years ago this can be 2 different areas too no ?

WiziusCareers1 · Answer

The archaeologist uses two premises to narrow the age range of the bone:

Initial Range:  1.5 to 2.0 million years (from radiometric dating).
 Plague Constraint:  The bone shows signs of damage from the mammoth plague, which ran rampant only from 1.9 to 2.0 million years ago.
 Conclusion:  Therefore, the bone must be 1.9 to 2.0 million years old.

Assumption:  The archaeologist assumes that the 1.9 to 2.0 million year range is the exclusive time frame during which the plague existed and could have caused the damage seen on the bone. The plague's timeline is used as a hard upper boundary.

A. Most other animal fossils uncovered in the area surrounding the dig site have been found by carbon-dating to be more than 2 million years old.

This is irrelevant.  The focus is on the specific hominid bone and its unique constraints (1.5 to 2.0 mya radiometric range and plague damage). The age of other animal fossils, especially those outside the established range of the hominid bone, does not affect the logic of the argument.

B. The mammoth plague killed mammoths and other large animals but not hominids.

This is  irrelevant.  The archaeologist observes damage associated with the plague, not necessarily that the plague killed the hominid. For instance, the hominid could have scavenged an infected animal or suffered damage from an environmental effect of the plague. As long as the damage is exclusive to the 1.9−2.0 mya window, the argument holds.

C. Ample archaeological evidence exists to support the hypothesis that the last outbreak of mammoth plague occurred 1.9 million years ago.

This would  strengthen the argument , not weaken it. If the plague ended at 1.9 mya, the bone's age would be tightly constrained between 1.9 and 2.0 mya (as it must be younger than 2.0 and could not have been infected earlier than 1.9 million years ago).

D. Fossils from the area that are between 1.5 and 1.8 million years old provide evidence of the mammoth plague.

This statement provides new information that  directly contradicts  the necessary exclusivity of the archaeologist's plague timeline.
If the plague was also active between 1.5 and 1.8 million years ago, then the presence of plague damage on the bone is consistent with any age in the initial radiometric range of 1.5 to 2.0 million years.
The constraint used to narrow the range is nullified. The new, wider plague range (1.5 to 2.0 mya) is identical to the initial radiometric range, meaning the plague evidence no longer helps to "further pinpoint" the age.
This casts the most doubt on the suggested range of 1.9 to 2.0 million years.

E. Fossils from the area that are more than 2 million years old provide evidence of the mammoth plague.

This information is outside the initial radiometric dating range for the hominid bone (1.5 to 2.0 mya). Since the bone cannot be older than 2.0 million years, the existence of the plague before that time does not affect the upper bound of the bone's age. The argument remains unchanged.

Archaeologist: The latest discovery at the dig site at Water Creek is

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Archaeologist: The latest discovery at the dig site at Water Creek is

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