On average, how often do impactors about 10 km in size, large enough to produce mass extinction, hit Earth?
A) once every century
B) once every thousand years
C) once every million years
D) once every hundred million years
E) once in Earth's history
D
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Describe the surface features of Venus. If the atmosphere is so thick and the planet is so hot, how do we know about these surface features on Venus?
What will be an ideal response?
True or False: When a photon scatters off an electron, the photon loses energy
1.False 2.True
What kind of pressure supports a white dwarf?
A) neutron degeneracy pressure B) electron degeneracy pressure C) thermal pressure D) radiation pressure E) all of the above
In an electrically neutral atom the number of protons in the nucleus is equal to the number of
A) electrons that surround the nucleus. B) neutrons in the nucleus. C) both of these D) none of the above