【霞姐GMAT】要你命的纸老虎IR（下）
Select Strengthen for the statement that would, if true, most strengthen the argument, and select Weaken for the statement that would, if true, most weaken the argument. Make only two seletions, one in each column.
genetic differences ➡ genetic-selection pressure on swamp sparrows in tidal marshes to become darker and grayer
很多同学在做IR时的策略，是有意的跳过多元推理（因为觉得这部分需要阅读的内容过长）。但霞姐却并不建议这么做。
Island Museum analyzes historical artifacts using one or more techniques described below—all but one of which is performed by an outside laboratory—to obtain specific information about an object's creation. For each type of material listed, the museum uses only the technique described:
Animal teeth or bones: The museum performs isotope ratio mass spectrometry (IRMS) in-house to determine the ratios of chemical elements present, yielding dues as to the animal's diet and the minerals in its water supply.
Plant matter: While they are living, plants absorb carbon-14, which decays at a predictable rate after death; thus radiocarbon dating is used to estimate a plant's date of death.
Fired-clay objects: Thermoluminescence (TL) dating is used to provide an estimate of the time since clay was fired to create the object.
Island Museum has acquired a collection of metal, fired clay, stone, bone, and wooden artifacts found on the Kaxna Islands, and presumed to be from the Kaxna Kingdom of 1250-850 BC. Researchers have mapped all the mines, quarries, and sources of clay on Kaxna and know that wooden artifacts of that time were generally created within 2 years after tree harvest. There is, however, considerable uncertainty as to whether these artifacts were actually created on Kaxna.
In analyzing these artifacts, the museum assumes that radiocarbon dating is accurate to approximately ±200 years and TL dating is accurate to approximately ±100 years.
For outside laboratory tests, the museum's first-year budget for the Kaxna collection allows unlimited IRMS testing, and a total of S7, 000 — equal to the cost of 4TL tests plus 15 radiocarbon tests, or the cost of 40 ICP-MS tests — for all other tests. For each technique applied by an outside lab, the museum is charged a fixed price per artifact.
Island Museum analyzes historical artifacts using one or more techniques described below—all but one of which is performed by an outside laboratory—to obtain specific information about an object's creation. For each type of material listed, the museum uses only the technique described:
Animal teeth or bones: The museum performs isotope ratio mass spectrometry (IRMS) in-house to determine the ratios of chemical elements present, yielding dues as to the animal's diet and the minerals in its water supply.
Plant matter: While they are living, plants absorb carbon-14, which decays at a predictable rate after death; thus radiocarbon dating is used to estimate a plant's date of death.
Fired-clay objects: Thermoluminescence (TL) dating is used to provide an estimate of the time since clay was fired to create the object.
Island Museum has acquired a collection of metal, fired clay, stone, bone, and wooden artifacts found on the Kaxna Islands, and presumed to be from the Kaxna Kingdom of 1250-850 BC. Researchers have mapped all the mines, quarries, and sources of clay on Kaxna and know that wooden artifacts of that time were generally created within 2 years after tree harvest. There is, however, considerable uncertainty as to whether these artifacts were actually created on Kaxna.
In analyzing these artifacts, the museum assumes that radiocarbon dating is accurate to approximately ±200 years and TL dating is accurate to approximately ±100 years.
For outside laboratory tests, the museum's first-year budget for the Kaxna collection allows unlimited IRMS testing, and a total of S7, 000 — equal to the cost of 4TL tests plus 15 radiocarbon tests, or the cost of 40 ICP-MS tests — for all other tests. For each technique applied by an outside lab, the museum is charged a fixed price per artifact.
我们在Budget内容卡下找相关信息，即Budget=7000=4TL+15RC=40IC，