Self-study
According to some astronomers, Support Earth is struck by a meteorite large enough to cause an ice age on an average of once every 100 million years. ███ ████ ████ ████████ ████████ ██████ ███ ███████ █████ ████ ██ ██ ███ ██████ ████ █████ ████ ██ ██████ ██ ████ █ █████████ ██ ███ ████ ███████ ████ ███████ ████████ ███████ ██ █████████ ███████ █████ ██ █ █████ ██ ███████ ███ ██████ ████ ████ █████████ ████████
Summarize Argument
The author advocates for funding to determine if Earth is protected from meteorites. This is because some astronomers claim that, in the past, large meteorites have struck Earth an average of once every 100 million years, and it’s been nearly 100 million years since the last strike. The author takes this as evidence that another strike is imminent.
Identify and Describe Flaw
The argument mistakenly assumes that because the average time between strikes has been 100 million years, that the next one must arrive about 100 million years after the previous strike. But averages don’t work like a fixed schedule—consider that the average between 50 million and 150 million is 100 million. The next strike could happen much later, or not at all. Additionally, there’s no reason to assume that this average will always hold. There may be far fewer or far more large meteorites now than in the distant past.
19.
The reasoning in the argument ██ ████ ███████ ██ █████████ ██ ███ ███████ ████ ███ ████████
a
makes a bold ████████████ ██ ███ █████ ██ ████████ ████ ███████████ ████ █ ████ ███████████ ███ █ ██████████ █████
The argument never establishes a high probability of a disastrous event. The author’s prescription would be reasonable if that risk had been established, but the past average doesn’t support a prediction of the next strike’s timing.
b
presumes, without providing ██████████████ ████ ███ ███████████ ██ █ ██████ ███████ █████████ ██ ███ ████████ ██ ███████ ███ █████ ███ ████████ ██████ █ ██████ ██ █████ ██ █████ ██ ████████ ██ █████
The argument does the opposite of this. It supports its prediction of the next strike’s timing by citing the fact that a strike has not occurred in nearly 100 million years.
c
moves from evidence █████ ███ ███████ █████████ ██ ██ █████ ██ █ ████████ ██████████ █████ ████ ███ ████ ████ █████ ████ █████
This describes how the argument misunderstands what the past average indicates. Just because there’s been a historic average of 100 million years between strikes does not mean that the next strike will occur about 100 million years after the previous one.
d
fails to specify ███ ██████████ █████ ██ ████ █ █████████ ██████ ██████ ██████ ███ █████████ █████ ██████ █████ ██ ███ ███
The possible effects of a future strike are irrelevant since the argument fails to establish that there will even be a strike.
e
presumes, without providing ██████████████ ████ ████ ████████ █████ ███ ██ █████ ██ █████ █████ █████████ ███████
The argument does not claim that large strikes can be deterred. It claims that the high probability of a large strike in the near future warrants funding to determine whether or not Earth is protected. The problem is that the high probability of a large strike isn’t established.