Self-study
Support Researchers have found that children in large families—particularly the younger siblings—generally have fewer allergies than children in small families do. ████ ███████████ ████ ████████ ██ █████ ██████ ███████ █████ ██████ ████ ██████ ██ ███████ ██████████
Summarize Argument: Phenomenon-Hypothesis
The researchers offer the hypothesis that being exposed to germs during infancy reduces the chance of people developing allergies. Their evidence is the fact that children in large families have fewer allergies than children in small families.
Notable Assumptions
Notice that we aren't told the differences in germ exposure that come from being in a large family versus a small family. There is a gap in this argument, in other words, between the concept of family size and the concept of exposure to germs. The researchers must assume that being in a large family generally exposes infants to more germs than being in a small family. To strengthen this argument, we might expect an answer choice that states this assumption or otherwise makes it more likely.
22.
Which one of the following, ██ █████ ████ ████████ ███ ████████████ ███████████
a
In countries where ███ ███████ ██████ ██ ████████ ███ ██████ ███ █████████ ████ ███ ████ ████████ ███ █████████ ██ █████████ ███ ██████████
This answer choice gives us an additional correlation between smaller family size and likelihood of allergies, but it doesn't bridge the gap between family size and exposure to germs. Remember that to strengthen this argument, we're looking to strengthen the idea that being in a larger family exposes infants to more germs than being in a smaller family, and so reduces risk of allergies. This answer choice is broad enough that the change in allergies could be explained by other factors than germ exposure within the family, such as environmental changes over the last century. So this doesn't strengthen the argument.
b
Children in small ████████ █████████ ███ ████ █████ ██ ████ ██████████ █████ ████ ████████ ██ █████ ████████ ███
This answer choice weakens the author’s argument. It suggests an alternative cause for the higher rates of allergies among children in smaller families: not exposure to germs, but the sorts of foods they eat.
c
Some allergies are ████ ████████████ █████ ████ ████████ ██████ ██ █████ ███████ ████ █████████ ███████████
This is completely irrelevant. The conclusion is about connecting family size, germ exposure, and developing allergies, not about the long-term consequences of some allergies and some germs.
d
Children whose parents ████ █████████ ████ ██ █████████████ ██████████ ██ ██████████ █████████ ███████████
This answer choice might seem to be implying that allergies are hereditary--but notice that the increased likelihood of allergies isn't necessarily blamed on genetics. It could also be environmental, given that children will likely grow up in similar surroundings to their parents. Either way, we have no idea how common such families are, and regardless of whether the risk of allergies is higher from the start due to genetics or environment, we want to know whether increased germ exposure in infancy will reduce that risk. This answer choice doesn't tell us anything about that.
e
Children from small ████████ ███ ███████ ███ ████ ██████ ███ ███ ████ ████ ██████ ██ ███████ █████████ ████ ████████ ████ █████ ████████ ███ ███████ ███ ████ ██████
Even though this answer choice doesn't specifically state the assumption at the heart of the argument--that children in large families are likely exposed to more germs--it strengthens the argument by showing a parallel case where the same assumption applies. Even children from small families, if exposed to other children in early infancy, are less likely to develop allergies than children exposed later. By giving us another example of a positive correlation between being exposed to more children, thus being exposed to more germs, and reduced risk of developing allergies, this answer choice strengthens the argument.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.