Self-study
Current evidence indicates that there is no methane on Planet 253. ██ ████ ██ ███ █████ ██ ██ ███████ ████ █████ ██ ██ ████ ██ ██████ ████ █████ ████████ ██████ ███████ ████████ ██ █████ ██ ██ ███████ ████ █████ ███ ██ █████████
Summary
The author concludes that if there’s no methane on Planet 253, then there is no life on Planet 253. Why? Because if there is no methane, then there are no microbes.
Missing Connection
We know that if there’s no methane, there’s no microbes. But how does this imply that if there’s no methane, there’s no LIFE? “No life” is a new concept in the conclusion. So, at a minimum, the correct answer must tell us what is sufficient to lead to “no life,” or what is required in order to have “life.”
To go further, we can anticipate a more specific connection. We already know from the premise that “no methane” implies “no microbes.” To get to “no life,” we just want to establish that “no microbes” implies “no life.” In other words, that life requires microbes.
26.
The conclusion drawn above follows █████████ ██ █████ ███ ██ ███ █████████ ██ ████████
a
There is, in █████ ██ ███████ ██ ██████ ████
The conclusion is conditioned on the hypothetical that there is no methane on Planet 253. Whether this hypothetical is true doesn’t prove the conclusion, because the conclusion already presumes that it’s true for the purpose of the argument.
b
If methane exists ██ ██████ ███ ████ ██ █████ ██ ████ ██ ██████ ███ █████████
(B) doesn’t establish what is sufficient to lead to “no life.” Since neither this answer nor the premises establish what leads to “no life,” (B) cannot make the argument valid.
c
If there is ██ ███████ █████████ ██ ██████ ███ ████ █████ ███ █████ ████ ███████ ██ ██████ ████
(C) doesn’t establish what is sufficient to lead to “no life.” Since neither this answer nor the premises establish what leads to “no life,” (C) cannot make the argument valid.
d
If there are ██ ████████ ██ ██████ ███ ████ █████ ██ ██ ████ ██ ██████ ████
We know that if there’s no methane on Planet 253, there’s no microbes on Planet 253. According to (D), that allows us to conclude there is no life on Planet 253, if there’s no methane.
e
If there is ███████ ██ ██████ ███ ████ █████ ████ ██ ████ ██ ██████ ████
(E) allows us to reach a conclusion that there IS life on Planet 253. But we want to establish that there is NO life on the planet. (E) is essentially a version of the conclusion that confuses sufficiency and necessity.