Scientific consensus supports the idea that living organisms require oxygen. Then, a scientist discovers a type of bacteria that metabolizes sulfur instead of oxygen, and thus survives in environments without oxygen. The scientist concludes that a diverse group of many different organisms could live in an oxygen-free environment. Why are some scientists skeptical of the scientist’s results and conclusion?
Answer
A
The results are different from the scientific consensus.
B
The conclusion shows the scientist is not open-minded.
C
The results will be difficult for scientists to reproduce.
D
The conclusion needs to be supported by more evidence.
Explanation
Finding one kind of bacterium that can survive without oxygen supports the claim that some life can exist in oxygen-free environments. It does not, by itself, show that a diverse group of many different organisms could live there. That broader conclusion needs evidence from additional organisms, so the best choice is D: the conclusion needs to be supported by more evidence.
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