The consensus among astronomers, based upon observations of the surfaces of pulsars, is that pulsars are spinning balls of neutrons compressed into a sphere some 10 kilometers in diameter with a mass roughly equal to that of our sun.
Conclusion
The observed properties of pulsars are consistent with the possibility that some pulsars are filled with quarks.
Evidence
Based on observations, astronomers think they are balls of neutrons. But if they were filled with quarks, they would have an overall positive charge, which would attract a layer of negatively charged particles that could support a crust of neutrons.
Evaluate
This argument is tricky to understand at first. From what astronomers can observe, they think pulsars are balls of neutrons. The author is suggesting an alternate interpretation (she's not insisting on it, just saying that it's also a possible interpretation).
Her alternate interpretation is essentially,
We're being asked about the claim . That claim was part of the author's attempt to show us how a pulsar filled with quarks would still end up resembling a neutron ball. She was saying, the core of quarks would give a positive charge, which would attract a layer of negatively charged particles, which could support an outer crust of neutrons.
When we see the word Because preface the claim we're asked about, it means that the claim is either a supporting premise for the other clause of that sentence. Ot it means that the claim describes a causal factor that results in the other clause of that sentence.
In this case, it seems to make more sense to interpret this as a Causal Because (as opposed to a Reasoning Because).
Goal
Look for an answer saying narrowly that this claim helps to explain why a quark-filled pulsar could potentially have an outer crust of neutrons.
Or look for an answer more broadly saying, .