howdoesitmatter wrote:
i eliminated A just because it said "absent from other types of organisms"
we are comparing bacteria with other types of organisms.
how can this be right answer then?
For any CR question, it is convenient to categorise each part of the given passage into one of the following five categories:
1. Premise, 2. Conclusion, 3. Background, 4. Counter-premise, 5.Counter-point (i.e., opposite to conclusion)
For the subject question:
Some microbiologists study bacteria in an effort to learn about the structure of the earliest organic life : Background
A flaw in this strategy is that bacteria are extremely varied: Conclusion
Indeed, any bacterium alive today is at the tail end of a long evolutionary process and has undergone considerable change since the earliest organic life appeared on Earth: Premise
Premise ---> conclusion. In a "weaken" question we need to find the option that weakens the bridge between the premise to conclusion.
Here, the argument is as follows:
Bacteria today has undergone evolution and changed a lot (premise) ---> Therefore bacteria are varied (conclusion)
You would notice that in the passage, the strategy of the scientists comes only as background information - whether it is right or wrong has no bearing to the argument itself. The part "absent from other kinds of organisms" raises question about the strategy of the microbiogists - it is another flaw, but that flaw is not a part of the conclusion.
So option A weakens the Premise to Conclusion bridge
used in the passage by stating that the bacteria are not varied.
Suppose the conclusion here would have been as follows:
A flaw in this strategy is that bacteria
are extremely varied are different from other species.
In this case Option A could not have been the right option, becaused then it would have strengthened the argument.