Correct Response: C. Variations in the density of space support the theory that a period of rapid inflation of the universe occurred fractions of a second into the Big Bang. Astronomers inferred that the universe rapidly expanded at the start of the Big Bang during a period of cosmic inflation. At the start of this brief period of inflation, quantum fluctuations occurred in the closely packed universe that later became the variations in density seen in today's greatly expanded universe. The proportion of elements in asteroids (A) provides information on the solar system's formation, not the inflationary period. The motion of receding galaxies (B) provides evidence of the universe's ongoing expansion, but not of the earliest inflationary period of its formation. Energy released from nuclear fusion (D) supports understanding of stellar evolution, but not the conditions hypothesized to have existed during cosmic inflation.
