For years, planetary scientists suspected that the sub-surface ocean of Saturn's moon Enceladus could harbor life. This hypothesis gained traction when the Cassini spacecraft detected hydrogen gas in the moon's plumes, suggesting hydrothermal activity. However, some researchers cautioned that abiotic chemical processes could also produce this hydrogen. To address this uncertainty, a team of researchers led by Antonin Affholder developed a statistical model to analyze the plume data. Their model determined that the observed levels of methane and hydrogen are highly consistent with biological methanogenesis, though they emphasize that non-biological explanations, while less probable, cannot yet be entirely ruled out.
Which choice best describes the overall structure of the text?
- AIt states a scientific consensus, describes how that consensus was challenged by new data, and presents a model that successfully established a new consensus.
- BIt describes an unexpected scientific discovery, details the technology used to make that discovery, and outlines two contrasting experiments designed to replicate it.
- It introduces a hypothesis, notes a discovery that supported it, presents a competing explanation for that discovery, and details a study that evaluated these explanations.Answer
- DIt argues in favor of a specific theory, presents empirical evidence that disproves an alternative theory, and calls for new technology to resolve a remaining dispute.