Text 1 Astronomers monitoring the atmosphere of Mars have detected seasonal spikes in methane gas. Because on Earth, the vast majority of methane is produced by living organisms (methanogens), the research team led by Dr. Gorski posits that these fluctuations are a strong biosignature. They conclude that microbial life likely exists beneath the Martian surface, waking up during warmer seasons to metabolize and release gas.
Text 2 Planetary geologist Dr. Chen cautions that methane is not solely a biological product. He points to a geological process called serpentinization, where water reacts with olivine-rich rocks to produce methane without any life forms involved. Since Mars is rich in olivine and possesses subsurface ice, Chen argues that the seasonal spikes are likely the result of abiotic geological cycles—rocks expanding and releasing trapped gas—rather than biological respiration.
Based on the texts, how would Dr. Chen (Text 2) most likely characterize the conclusion presented by Dr. Gorski in Text 1?
As premature, because it overlooks known geological processes that can produce the same atmospheric signals as life
As irrefutable, because the specific seasonal timing of the methane spikes can only be explained by biology
As improbable, because methane breaks down too quickly in the Martian atmosphere to be detected at all
As innovative, because it serves as the first proof that water exists in liquid form on the Martian surface
Correct Answer: A
Choice A is the best answer. Text 1 concludes that methane spikes = life. Text 2 argues that geological processes (serpentinization) also produce methane spikes. Therefore, Chen would characterize Gorski’s conclusion as premature/flawed because it ignores the non-biological (abiotic) explanation for the same data.
Choice B is incorrect because Chen is arguing against the conclusion that biology is the only explanation. Choice C is incorrect because Chen admits methane is being detected; he disputes the source of it. Choice D is incorrect because the presence of liquid water is part of Chen's premise, not the "innovative" conclusion being challenged.