Question 1: Why do astronomers and physicists believe the Universe
The light from distant galaxies is is too hard to see.
The light from distant galaxies appears to Doppler-shifted.
The temperature of the Universe is getting cooler and cooler.
Question 2: Which observed feature of our visible Universe has not
been explained through the Big Bang theory of cosmology?
The absence of isolated magnetic charge, known as magnetic monopoles
The temperature of the cosmic background radiation
Why there is so much more hydrogen than helium today
Question 3: How were the heavy elements like carbon and iron believed
to have been made during the expansion of the Universe?
By confinement of quarks and gluons into baryons and mesons
By decoupling of matter and radiation
By nuclear fusion of light nuclei in the middle of stars, then ejection
via supernova explosions
Question 4: In superstring theories, how many spacetime dimensions
must remain tiny as the visible Universe expands?