According to the passage, the author considers the reduction of energy in an empty region of space to which a real particle has been added to be

A．uncertainties.
B．dependent conditions.
C．incidental thought.
D．events that may occur.

A．time sense in animals.
B．how man's time sense separates him from animals.
C．man's preoccupation with past and future events.
D．how apes understand time relationships.