Question

Difficulty: HardStrengthen

Geochemists analyzing vapor plumes venting from the fracture zones of an icy satellite observed elevated concentrations of molecular hydrogen and methane. Laboratory simulations establish that while hydrothermal serpentinization reactions produce abundant hydrogen, the abiotic reduction of dissolved carbon dioxide into methane proceeds far too slowly under the moon's inferred core temperatures to yield the observed methane concentrations. On this basis, the researchers conclude that biological methanogenesis by chemoautotrophic microorganisms in the sub-surface ocean is the primary source of the plume methane.

True or False: The finding that primordial methane trapped in sub-surface clathrate hydrates during the satellite's initial accretion would have completely decomposed and outgassed within the first billion years of the solar system's formation logically strengthens the researchers' conclusion.

Answer: Answer

Answer

True
The claim is True because ruling out the persistence of primordial methane reservoirs eliminates a major alternative abiotic explanation, directly bolstering the inference that active microbial methanogenesis is responsible for the detected plume composition.

Step-by-Step Solution

1
Isolate the argument's core premises and conclusion
Premises establish that real-time abiotic synthesis of methane via serpentinization is kinetically hindered at ambient temperatures; Conclusion infers that chemoautotrophic microbes are producing the methane.
Accurate structural breakdown identifies the evidential basis and the scope of the author's causal claim.
2
Identify the unstated assumption and logical vulnerability
The argument assumes that if methane cannot be synthesized abiotically in the present day, it must have a modern biological origin, overlooking passive abiotic origins such as legacy primordial reserves.
Strengthen questions frequently target unaddressed rival explanations for an observed physical phenomenon.
3
Assess the logical impact of the supplementary finding
Confirming that primordial clathrates completely dissipated billions of years ago rules out ancient accretionary storage as the source of current plume emissions.
Eliminating a competing non-biological mechanism increases the probability that the active biological mechanism is correct, thereby strengthening the argument.

Key Concept

Strengthening causal arguments by eliminating alternative non-biological hypotheses
Estimated Time:1m 15s
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