The most important event during the Cambrian period was the
A) emergence of the fishes.
B) ability of organisms to form an outer skeleton.
C) emergence of the trilobite.
D) ability of organisms to develop lungs.
Answer: B
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Where do the majority of naked-eye stars fall on the H-R diagram? Is this true of the majority of stars close to our Sun as well?
What will be an ideal response?
What is the visible surface of the Sun called?
A. the radiative zone B. the chromosphere C. the photosphere D. the corona
The binding energy of the hydrogen atom in its ground state is -13.6 eV. What is the energy when it is in the n = 5 state?
A) 2.72 eV B) -2.72 eV C) 0.544 eV D) -0.544 eV E) None of the given answers are correct.
The wave function of an electron in a rigid box (infinite well) is shown in the figure. If the electron energy 98.0 eV, what is the energy of the electron's ground state? (mel = 9.11 × 10-31 kg)
A) 6.13 eV B) 3.92 eV C) 10.9 eV D) 24.5 eV