PrepTest 32, Section 2, Question 24
Science journalist: Brown dwarfs are celestial objects with more mass than planets but less mass than stars. They are identified by their mass and whether or not lithium is present in their atmospheres. Stars at least as massive as the Sun have lithium remaining in their atmospheres because the mixing of elements in their internal nuclear furnaces is incomplete. Stars with less mass than the Sun have no lithium because the element has been fully mixed into their nuclear furnaces and consumed. A brown dwarf does not have a fully functional nuclear furnace and so its lithium cannot be consumed.
Science journalist: Brown dwarfs are celestial objects with more mass than planets but less mass than stars. They are identified by their mass and whether or not lithium is present in their atmospheres. Stars at least as massive as the Sun have lithium remaining in their atmospheres because the mixing of elements in their internal nuclear furnaces is incomplete. Stars with less mass than the Sun have no lithium because the element has been fully mixed into their nuclear furnaces and consumed. A brown dwarf does not have a fully functional nuclear furnace and so its lithium cannot be consumed.
Science journalist: Brown dwarfs are celestial objects with more mass than planets but less mass than stars. They are identified by their mass and whether or not lithium is present in their atmospheres. Stars at least as massive as the Sun have lithium remaining in their atmospheres because the mixing of elements in their internal nuclear furnaces is incomplete. Stars with less mass than the Sun have no lithium because the element has been fully mixed into their nuclear furnaces and consumed. A brown dwarf does not have a fully functional nuclear furnace and so its lithium cannot be consumed.
Science journalist: Brown dwarfs are celestial objects with more mass than planets but less mass than stars. They are identified by their mass and whether or not lithium is present in their atmospheres. Stars at least as massive as the Sun have lithium remaining in their atmospheres because the mixing of elements in their internal nuclear furnaces is incomplete. Stars with less mass than the Sun have no lithium because the element has been fully mixed into their nuclear furnaces and consumed. A brown dwarf does not have a fully functional nuclear furnace and so its lithium cannot be consumed.
Which one of the following is most strongly supported by the science journalist's statements?
Any celestial object without lithium in its atmosphere is a star with less mass than the Sun.
Any celestial object with lithium in its atmosphere has a nuclear furnace that has incompletely mixed the object's elements.
No celestial object that has no lithium in its atmosphere is a brown dwarf.
No celestial object with lithium in its atmosphere has less mass than the Sun.
No celestial object less massive than a brown dwarf has lithium in its atmosphere.
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