During a protostar's T Tauri phase, it:
A) begins a period of reduced activity.
B) expands dramatically.
C) lies on the main sequence.
D) may develop very strong winds.
E) changes its spin direction.
D
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When did life first appear on Earth?
a. 14 billion years ago b. 400 million years ago c. 4.6 billion years ago d. 65 million years ago e. 3.4 billion years ago
Based on what you learn about jovian moons by watching the videos or reading your textbook, what types of evidence for recent or ongoing geological activity have been observed on one or more jovian moons?
a. ice crystals being sprayed out into space b. surfaces with very few impact craters c. river valleys feeding into surface lakes of very cold liquids d. active volcanoes e. river valleys feeding into surface lakes of liquid water f. large, violent storms swirling in counterclockwise directions
Which contains more moles of material: 80 grams of helium gas (He, having atomic weight 4.0 g/mol) or 400 grams of argon gas (Ar, having atomic weight 40 g/mol)?
A) helium B) argon C) Both contain the same number of moles.
If a planet has 3 times the radius of the Earth, but has the same density as the Earth, what is the gravitational acceleration at the surface of the planet? (g = 9.80 m/s2)
a. 29.4 m/s2 b. 88.2 m/s2 c. 265 m/s2 d. 3.27 m/s2