Question

a recent study reports that ionic liquids—which have the potential to support metabolic processes essential to life—can form naturally from ingredients likely present on many rocky worlds. this is significant because currently, the habitable zone, the region around a star where life seems possible, is defined primarily by conditions allowing liquid water. the researchers tested over 30 nitrogen - containing organics with sulfuric acid, under a range of temperatures and pressures, and in nearly every scenario, pockets of ionic liquid formed. remarkably, these liquids persisted up to 180 °c and at pressures far below earth’s atmospheric level—conditions that would quickly destroy liquid water. thus, ______
which choice most logically completes the text?
a) planets lacking liquid water at moderate temperatures are unlikely to harbor any form of life, regardless of the presence of other stable liquid phases.
b) the ability of ionic liquids to persist under conditions lethal to water demonstrates that metabolic activity occurs in planetary environments previously deemed uninhabitable.
c) the concept of planetary habitability may need to expand beyond current criteria to include certain environments where liquid water cannot exist.
d) planets with nitrogen - containing organics and sulfuric acid may host life due to the improved temperature and pressure conditions precipitated by their presence.

Explanation:

The text notes that current habitability is defined by liquid water, but ionic liquids (which can support life's metabolic processes) form and persist in conditions that destroy liquid water. This implies the existing habitability framework is too narrow, so expanding it to include these water-free environments is the logical conclusion. Option A contradicts the text's implication that other liquids could support life. Option B overstates the evidence—ionic liquids have the potential to support metabolism, but the text does not confirm metabolic activity actually occurs in these environments. Option D incorrectly links the presence of the ingredients to "improved" conditions, rather than focusing on the need to redefine habitability.

Answer:

C) the concept of planetary habitability may need to expand beyond current criteria to include certain environments where liquid water cannot exist.