Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that certain bacteria detect a particular shade of red by monitoring how much energy their chlorophyll produces. This is based on the fact that, when placed into a test tube that has different areas lit with different colors of light, the bacteria move only into areas lit with that shade of red. In addition, the bacteria’s chlorophyll allows them to produce energy more effectively from this shade of red than from any other color.
Notable Assumptions
The author assumes there’s no other explanation for why the bacteria moves only to those areas that are lit with that shade of red.
A
If the chlorophyll is removed from the bacteria, but the bacteria are otherwise unharmed, they no longer show any tendency to move into the areas lit with the particular shade of red.
This strengthens the argument by helping to establish a connection between chlorophyll and moving to that shade of red.
B
The bacteria show little tendency to move into areas containing light in colors other than the particular shade of red, even if their chlorophyll can produce some energy from light in those colors.
This is consistent with the author’s hypothesis. Because those other shades don’t produce energy as effectively, the bacteria tends not to move to those areas.
C
The areas of the test tube lit with the particular shade of red favored by the bacteria are no warmer, on average, than areas lit with other colors.
This strengthens the argument by eliminating the alternate explanation that the bacteria are moving to the areas that are warmer rather than because of the greater energy produced by their chlorophyll.
D
The bacteria show no tendency to move into areas lit with blue even when those areas are lit so brightly that the bacteria’s chlorophyll produces as much energy in those areas as it does in the red areas.
This presents evidence inconsistent with the author’s hypothesis. If the bacteria don’t move to areas lit in blue, even if those areas produce as much energy as the areas lit in the particular shade of red, this suggests the bacteria isn’t moving due to its chlorophyll’s energy.
E
There are species of bacteria that do not contain chlorophyll but do move into areas lit with particular colors when placed in a test tube lit with different colors in different places.
Other bacteria might move toward other lights for other reasons besides chlorophyll. The author never suggested that no bacteria can ever move to any lights through other methods. The conclusion is just that this particular bacteria detects the red light through chlorophyll.
Summary
After a nuclear power plant accident, radioactive isotopes of iodine, tellurium, and cesium were found in the atmosphere downwind. No heavy isotopes were found. The material either came from spent fuel rods or the plant’s core. Spent fuel rods never contain significant quantities of tellurium, and radioactive material ejected directly from the core would include heavy isotopes. However, steam which may have been in contact with the core was released from the plant. The core contains iodine, tellurium, and cesium, which are easily dissolved by steam.
Strongly Supported Conclusions
The radioactive material found in the atmosphere was carried by the steam released from the plant.
A
Radioactive material ejected into the environment directly from a nuclear power plant’s core would not include tellurium isotopes.
This answer is unsupported. We don’t know from the stimulus whether material ejected directly from the core would not include tellurium. We only know that material ejected directly from the core would definitely include heavy isotopes.
B
The radioactive material detected by the researchers was carried into the atmosphere by the steam that was released from the plant.
This answer is strongly supported. If all three radioactive isotopes found are easily dissolved by steam, and all three are found in the plant’s core, then it’s likely that the found material was carried into the atmosphere by the steam.
C
The nuclear power plant’s spent fuel rods were not damaged.
This answer is unsupported. We don’t know from the stimulus whether the spent fuel rods were damaged or not. We only know information about what isotopes spent fuel rods contain.
D
The researchers found some radioactive material from spent fuel rods as well as some material that was ejected into the atmosphere directly from the plant’s core.
This answer is anti-supported. We know from the stimulus that material ejected directly from the core would include heavy isotopes, yet the researchers did not find any heavy isotopes.
E
Spent fuel rods do not contain heavy isotopes in significant quantities.
This answer is unsupported. We don’t know from the stimulus whether spent fuel rods do not contain heavy isotopes. We only know that spent fuel rods do not contain significant amounts of tellurium.
Summarize Argument
The author concludes car manufacturers will use fewer physical test crashes if simulations provide as much information about safety features as physical crashes. Why? Because running simulations is far cheaper.
Notable Assumptions
The author assumes there’s no advantage to physical test crashes over simulated crashes that would outweigh the higher cost. In particular, this means assuming simulations would provide at least as much information not related to safety features as physical crashes and that fewer test crashes would be legally permitted.
A
Apart from information about safety features, actual test crashes provide very little information of importance to automobile manufacturers.
This makes concrete the author’s assumption that physical crashes provide no more non-safety information than simulated crashes. It means manufacturers wouldn’t lose out on other information by switching from physical crashes to simulated ones.
B
It is highly likely that within the next 20 years computer simulations of automobile crashes will be able to provide a greater amount of reliable information about the effectiveness of automobile safety features than can be provided by actual test crashes.
This supports future manufacturers using simulated crashes—not reducing the number of physical crashes. It doesn’t address the author’s assumption that there’s no advantage to physical crashes over simulated crashes.
C
If computer simulations will soon be able to provide more information about the effectiveness of automobile safety features, automobile manufacturers will soon be able to produce safer cars.
This suggests simulated crashes are useful, not that physical crashes are useless. It doesn’t address the author’s primary assumption—that there’s nothing manufacturers can get from physical crashes they can’t get from simulated crashes.
D
The cost per automobile of testing and designing safety features is decreasing and will continue to decrease for the foreseeable future.
This is irrelevant. It doesn’t suggest that cost considerations will become more significant in the future when deciding whether to conduct physical or simulated crashes.
E
For years, the aviation industry has been successfully using computer simulations of airplane crashes to test the effectiveness of safety features of airplane designs.
This is irrelevant. It suggests crash simulations are useful in an analogous field: aviation. It doesn’t say that either airplane or automobile manufacturers will run fewer physical test crashes if simulations improve.