Summarize Argument: Phenomenon-Hypothesis
The author concludes that the melting of the ice contributed to the earthquakes in Sweden at the end of the last Ice Age. This is because melting ice reduced the weight pressing on the earth’s crust, which caused lasting cracks to form in the earth’s crust.
Notable Assumptions
The author assumes that cracks in the earth’s crust make earthquakes more likely to happen, or themselves constitute earthquakes. He also assumes that Sweden is situated in a location where the cracks caused by melting ice caused earthquakes.
A
The earth’s crust tends to crack whenever there is a sudden change in the pressures affecting it.
This more or less restates a premise. We need to strengthen the connection between the premises and the conclusion.
B
There are various areas in Northern Europe that show cracks in the earth’s crust.
The author never claims Sweden is the only place in Northern Europe where such earthquakes happened.
C
Evidence of severe earthquakes around the time of the end of the Ice Age can be found in parts of northern Canada.
While this strengthens the claim melting ice correlates with earthquakes, the author makes a causal claim. We want to strengthen the causation.
D
Severe earthquakes are generally caused by cracking of the earth’s crust near the earthquake site.
Cracks in the earth’s crust cause earthquakes. This strengthens the causal relationship that the author claims exists by clarifying how melting ice relates to earthquakes.
E
Asteroid impacts, which did occur at the end of the Ice Age, generally cause severe earthquakes.
This totally weakens the author’s argument. Asteroids, not melting ice, were responsible for the earthquakes.
Summary
A hummingbird’s egg accounts for 15 percent of an adult hummingbird’s weight. An adult goose is much larger than a hummingbird, but a goose’s egg accounts for only 4 percent of an adult goose’s weight. An adult ostrich is much larger than a goose, but ostrich eggs only account for 1.6 percent of an adult ostrich’s weight.
Strongly Supported Conclusions
The larger a bird species is, the smaller the ratio is between egg weight and the body weight of an adult bird.
A
The eggs of different bird species vary widely in their ratio of volume to weight.
This answer is unsupported. In the stimulus, we are comparing egg weight and volume to the weight and volume of an adult bird. This answer is comparing egg weight and volume of one species compared to the egg weight and volume of another.
B
The smaller and lighter the average adult members of a bird species are, the larger and heavier the eggs of that species are.
This answer is unsupported. From the stimulus, we only know that the ratio between the weight and volume of an egg increases the smaller the adult bird is. This doesn’t mean that the eggs are larger, just that they account for a bigger proportion of an adult’s weight.
C
The ratio of egg weight of a species to body weight of an adult member of that species is smaller for larger birds than for smaller ones.
This answer is strongly supported. This answer accurately captures the comparative difference of proportion between egg weight and volume of different bird species.
D
The size of birds’ eggs varies greatly from species to species but has little effect on the volume and weight of the adult bird.
This answer is unsupported. We don’t know from the stimulus anything about the size of any adult bird’s eggs. Rather, we only know something about the proportion of egg weight and volume compared to an adult bird.
E
Bird species vary more in egg size than they do in average body size and weight.
This answer is unsupported. We don’t know from the stimulus whether bird species vary in egg size at all. We only know that in different species of birds, egg weight and volume accounts for a different proportion of an adult bird’s weight.