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passage 2
P1
A vigorous debate in astronomy centers on an epoch in planetary history that was first identified by analysis of rock samples obtained in lunar missions. ██████████ ██████████ ████ ███ █████ ███████ ██ ███ ████ ████ ███████ ██ █ ████████ ███████████ ██ ██████ █████████████ ████ ███████ █████ █████████ █████████ ████ █████ ███████████ ██████ ███████████ ████ ████ ███████████ ████ ████████ ███ ████
Phenomenon ·
Late heavy bombardment
4 billion years ago, Moon and Earth were both massively bombarded with projectiles.
P2
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Hypothesis 1 ·
Large asteroid or comet disintegration
Evidence: size of lunar craters is large, suggests a large asteroid or comet broke apart and bombarded inner solar system with debris.
Hypothesis 2 ·
"LHB" is just a part of an even longer period of bombardment
"LHB" is part of a continuous bombardment that lasted billions of years. "LHB" just happened to be last and hence obliterated evidence of earlier impacts.
Hypothesis 3 ·
LHB only affected Earth-Moon system
Contra hypothesis 1 which claims that LHB affected entire inner solar system (Mars, Earth, Venus, and Mercury).
P3
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Evidence Supporting Hypothesis 1 ·
Mars rock found on Earth
Mars rock dates to same time as LHB, suggesting that Mars experienced bombardment too
Conclusion ·
LHB wasn't just an Earth-Moon phenomenon
At least Mars experienced it too.
Further Research ·
To decide between the different hypotheses
Passage Style
Critique or debate
Phenomenon-hypothesis
9.
The author's attitude toward arguments ████ █████ ██ █████ ██ ███ ████████ ██ ███ ████ █████████ ██ ███ ███████ ██ █████ ████ ████
a
ambivalence because the ██████ ██ ███ ██████ █████████ ██ █████ ██ ██ ████ ████ █████████ ███ █████████ ██ ███████
b
caution because even ██ ███ ██████ ██████████ ███ ██████ ███████ ███ ██ ███████ ██ ██ ██████ ██ ████ ███████ ███████████ ███████ ███████ ████████
c
skepticism because it █████ ████████ ████ █ ████ █████ ███████ ████ ███ ███ ████ ████ ██ █████ █████ █████ █████████
d
curiosity because many ███████ ██ ███ ██████ ██████████████ ███████ ███ ████████ █████████ ███ ███ ██████ ████████ ████ ███ ███ ████ █████████
e
outright acceptance because ███ ███████ ██ ███ ████ ████ ████ ████████████ ████████████