Multiple Choice
The figure below shows a graph of the scale factor, RU, with time, for three different scenarios.The age of the universe is the difference between now and the time at which RU is zero.Which curve illustrates a universe that is expanding at a constant rate? 
A) A
B) B
C) C
D) All of these curves are valid for constantly-expanding universe.
E) None of these curves is valid for constantly-expanding universe.
Correct Answer:
Verified
Correct Answer:
Verified
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