Ben learns that a type of radiation called cosmic microwave background (cmb) provides evidence that supports the big bang theory. which statement best explains why cmb is evidence that supports the big bang theory?
a. the temperature of cmb is slowly increasing over time.
b. cmb fills the universe and can be detected in every direction.
c. the frequency of cmb is slowly increasing over time.
d. cmb is constantly being emitted by stars throughout the universe.