The fact that many of the larger Jovian moons orbit nearly in the equatorial plane of their host world, moving in the same direction as their planet's spin, suggest that they
A) formed from a rotating disk of gas and dust like a miniature solar system
B) were spun out from the rapidly spinning host world as it formed
C) formed elsewhere in the solar system and were later captured
D) were formed from a giant impact between the host world and another body
Question 2
Why have studies of the geological record not enabled us to determine how life on Earth originated?
A) the first living organisms would have left absolutely no trace of their existence
B) life was planted on the Earth by an advanced civilization so there is no evidence in the geological record to find
C) the geological record does not extend back to the time that life originated
D) the oldest rocks are too deep inside the Earth for us to retrieve
The tenuous atmosphere of Mars, visible on the horizon in this low-orbit photo
Jupiter and Its Largest Moons
Moon orbit
A taxonomy of primate social systems. Larger symbols indicate adults.
The North and South Equatorial Currents
Chain of Transmission of Microorganisms from Host to Victim