500
Which of the following, if true, would undermine the validity of the author's assumption about the impact of mechanical clocks ("When the first... the laboratory") in lines 37-42?
a. People were oblivious to time on a physical level before clocks were invented.
b. People have always perceived time as composed of discrete, uniform intervals.
c. Body time does not move at a constant rate.
What is b. People have always perceived time as composed of discrete, uniform intervals.