Self-study
Measurements of the extent of amino-acid decomposition in fragments of eggshell found at archaeological sites in such places as southern Africa can be used to obtain accurate dates for sites up to 200,000 years old. ███████ ███ █████████████ ██ ██████ ██ ████ █████████ ███ █████████ ███ ██ ████ ██ ██████ ████████ █████ ███ █████ ██████ █ ███████ █████ ███ ██ ██████ ████████
The Stimulus' Claims Distilled
In MSS questions, we can just treat the stimulus as a big ol’ list of rules – 10 commandments style – any one of which could hold the key to the correct answer. Here’s the list:
- We can look at decomposing amino acids in eggshells to determine the age of archaeological sites.
- Decomposition is slower in colder climates.
- In some relatively warm climates (like southern Africa), 200,000 years old is the limit.
- In some relatively cool climates, we can almost hit a million years.
The answer really could come from anywhere – there are no obvious “link this up with that” inferences, but at the same time there’s like a million random valid statements we could draw from these rules. In situations like this, process of elimination is the way.
8.
The information above provides the ████ ███████ ███ █████ ███ ██ ███ █████████ ████████████
a
The oldest archaeological █████ ███ ███ ██ ████████ ███████ ███ ██████ ██ ██████ ███████ ██ ███ ██████
(A) would be right if it said the oldest archaeological sites that we can accurately date using the eggshell technique are in cooler regions.
Southern Africa could still have the oldest sites – they’d just need to be dated using different methods.
b
The amino-acid decomposition ████ ███████ █████████ ██ ██ ████ ██ ██████ ████ ███ ████ █████ ██ █████ ███████ ██████ █████ ██ ███████ ██████████████ ██████
(B) would find support if the stimulus featured claims about how eggshells are necessary to obtain accurate dates or the only source of material that can be dated in this way.
c
If the site █████ █████ ███ ████ ███████ ██ █████ ███████████ ████████ ████████████ ██████ ███ ████ ███ ████████ ███ ████ ██ ███ █████ ███████████ ██ ███ █████████ ██ ████ ██████ ██ █████ ████████ ████████
The word unsuspected is key here. The stimulus tells us 1) we measure decomposition to obtain accurate dates, and 2) decomposition rates vary with climate. If there are large, unsuspected climatic fluctuations, there will be a difference between the actual rate of decomposition and the assumed rate of decomposition, resulting in potentially-inaccurate data.
The weakly-worded “less likely to yield accurate results” is nice as well. Much better than “will certainly yield wildly inaccurate results,” for example.
d
After 200,000 years ██ █ ████ ████████ ████ ████ █████████ ██ ███ █████ █████ ██ █ ████████ ██ ████████ ████ █████ ███████ ████████ ███ ██████ ████ ███ █████████ ████ ████ ██████████ ███ ████ ████ ██ ██████ ██ ████████ ███ ███████████ ██ ███ ██████████
(D) is wrong because it assumes a linear rate of decomposition. 200,000 is indeed ⅕ of a million, but perhaps amino acid decomposition starts off fast and slows over time.
“No longer be suitable for examination by the technique” is a bit weird, too. The technique itself measures the proportion of decomposed material, so the parts that have decomposed are suitable for examination.
e
Fragments of eggshell ███ ████ ██████ ██ ██ █████ ██ ███████ ██████████████ █████ ██ ████ ███████ ██ ███ █████ ████ ██ ████ █████ ██ ██████ ████████
(E) just ventures off into fully unsupported nonsense. It’s a claim about where eggs are found, whereas the stimulus is about how we measure decomposing amino acids in the eggs we find, however many there are.