Measurements of the extent of amino-acid decomposition in fragments of eggshell found at archaeological sites in such...

Naz June 5, 2014

So we are dealing with a Must Be True question. Our correct answer will be 100% supported by the passage.

The passage tells us that eggshell fragments can be used to obtain accurate dates for sites in southern Africa up to 200,000 years old. This occurs through a process of looking at the decomposition of the shells. We are also told that decomposition is slower in cool climates. So this technique can be used to date sites almost a millions years old in cooler regions.

Answer choice (A) is not supported by the passage. Just because the sites in southern Africa aren't cool enough enable slower eggshell decomposition, that doesn't mean there isn't a different way to date the site to show it is older than 200,000 years old. The passage does not tell us that eggshell decomposition is the only way to date a site, nor does it tell us that it is the best or most accurate way. Thus, based solely on the information given to us in the passage, we do not necessarily know that the oldest archaeological sites are not in southern Africa.

Answer choice (C) is 100% supported by the passage. The process of dating using eggshells takes "measurements of the extent of amino-acid decomposition in fragments of eggshells" found at archaeological sites in order to determine "accurate dates for sites." So, if at different times a specific site was subject to differing climate fluctuations, the decomposition of the eggshell fragments, being slower in cool climates than warmer ones, will vary. Therefore, the resulting date will not be as accurate because the decomposition that the dating is based on will not be consistent.

Hope that helps! Let us know if you have any other questions.