The origin of Earth's primitive ozone layer
A) is attributed to photosynthesis.
B) traces back to the Cambrian period.
C) is attributed to volcanic eruptions.
D) helped to form the oceans.
Answer: D
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A refrigerator extracts 65.0 J of heat from a heat reservoir at 
If the coefficient of performance of the refrigerator is 2.50, then how much heat is discharged out of the refrigerator?
A. 125 J B. 91.0 J C. 75.0 J D. 55.0 J
The ground state of hydrogen has two closely-spaced energy levels, where oneelectron is spinning up and the other is spinning down. This energy transition corresponds to releasing excess energy as a photon at what wavelength?
a. 21 centimeters b. 21 millimeters c. 21 meters d. 22.2 centimeters e. 22.2 millimeters
If the accuracy in measuring the velocity of a particle increases, the accuracy in measuring its position will
A) increase. B) decrease. C) remain the same. D) It is impossible to say since the two measurements are independent and do not affect each other.
Consider two copper wires of equal cross-sectional area. One wire has 3 times the length of the other. How do the resistances of these two wires compare?
A) Both wires have the same resistance. B) The longer wire has 1/3 the resistance of the shorter wire. C) The longer wire has 3 times the resistance of the shorter wire. D) The longer wire has 9 times times the resistance of the shorter wire. E) The longer wire has 27 times times the resistance of the shorter wire.