Self-paced
P1
According to the theory of gravitation, every particle of matter in the universe attracts every other particle with a force that increases as either the mass of the particles increases, or their proximity to one another increases, or both. ███████████ ██ ████████ ██ █████ ███ ██████████ ██ ██████ █████████ ███ ███ ██████ █████████ ███
Theory of gravitation ·
Gravity is believed to have shaped the structure of the universe
Gravity = every particle of matter attracts every other particle based on the mass of particles and how close they are to each other
Puzzling phenomenon ·
90% of the universe seems to be missing
The observable mass isn't enough to explain the universe.
Cosmologists' hypothesis ·
Dark matter
P2
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Elaborate on dark matter ·
Dark matter might be neutrinos
But, neutrinos have been assumed to have no mass. So, how could they be the dark matter that helps the universe take its shape? (Come back to this paragraph for details of exactly what neutrinos are.)
P3
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Elaborate on dark matter ·
Neutrinos do have mass, so they can, in theory, be dark matter
Research shows that neutrinos can oscillate. And oscillation requires mass. (Come back to this paragraph for details of exactly what oscillation is.)
P4
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Limits of neutrinos as dark matter ·
Neutrinos are at most about 20% of dark matter
There must be other particles that make up the rest of dark matter. Cosmologists still find the neutrino theory of dark matter helpful.
Passage Style
Phenomenon-hypothesis (RC)
Single position
15.
Based on the passage, the ██████ ████ ██████ █████ █████ ███ ██ ███ █████████ ██████
a
Observable matter constitutes ██ █████ ██ ███████ ██ ███ ████ ██ ███ █████████
b
Current theories are █████████ ██ ███████████ ███ █████ ████ ██████ ███ █████████ ██ ███ ████████ ██ ███████ ███ ████████
c
The key to ███ ███████ ██ ████ ██████ ██ ███████████ ███ █████ ████ ██ █ █████████
Not supported, because after telling us that the estimated mass of neutrinos is between 0.5 to 5 electron volts, the author doesn’t suggest that we need to figure out the exact mass.
d
It is unlikely ████ ███ █████ █████ ████ ███████████ ████ ██ ████████ ██ ███████ ███ ███ ████████████ ██ ███ ████████ ████ █████████
This is the best answer. All other answers are either anti-supported or have no support. (D) has at least some support, given that the author never questions gravity as the force that explains the organization of the universe. The search for the “missing mass” assumes the theory that gravity formed the structure of the universe is correct.
e
Neutrinos probably account ███ ████ ██ ███ ██████████ █████████ █████