A. To explain why formal legal codes were developed
B. To explain what factors caused the destruction of several early states
C. To stress the importance of agricultural workers
D. To further describe the organization of states
What is the professor's opinion about the environmental approach`?
A. It will remain popular for a long time.
B. It does not help explain how early states formed.
C. Some evidence supports it, but other evidence contradicts it
D. It should be applied when analyzing hierarchies
What is the main propose of the lecture'?
A. To compare solutions to the greenhouse-gas problem
B. To examine methods used to study star formation in other solar systems
C. To discuss evidence for liquid water on young Earth and Mars
D. To discuss attempts to solve a puzzle related to the Sun
Why is geological evidence of liquid water on Earth and Mars three to four billion years ago problematic
A. It suggests that the solar system is younger than it could possibly be.
B. It suggests that the young Sun was less bright than it is today.
C. It challenges the prevailing model of star formation.
D. It contradicts theories about the beginning of the universe
Why did the greenhouse-gas solution fail to explain the early presence of liquid water on Earth and Mar
Click on 2 answers.
A. The types of gases that were present in their atmospheres could not have caused temperatures
B. There was insufficient carbon dioxide in their atmospheres to produce a greenhouse effect.
C. Solar radiation would have destroyed the ammonia in their atmospheres.
D. Clouds of ammonia would have lowered temperatures by blocking out sunlight.
Why does the professor mention the solar wind?
A. To explain a way the Sun is losing mass
B. To point out that it was less intense billions of years ago
To suggest a reason for early climate differences between Earth and Mars
D. To explain the importance of solving the faint-young-Sun paradox