Question

which evidence supports the big bang theory?○ planetesimals form in debris disks.○ most galaxies are moving toward us.○ uniform background radiation is detected in every direction.○ galaxies spin faster than they should based on visible matter.

Explanation:

• Planetesimal formation relates to solar system formation, not the Big Bang.
• Most galaxies are moving away from us (redshift), not toward us, which is evidence for cosmic expansion but this option is incorrect.
• Cosmic Microwave Background (CMB) radiation is uniform microwave radiation detected in all directions, a key leftover heat signature from the early hot universe predicted by the Big Bang theory.
• Galaxy rotation speed discrepancy led to the theory of dark matter, not direct Big Bang evidence.

Answer:

Uniform background radiation is detected in every direction.