Question

what fact do scientists believe provides evidence for the big bang theory?
a. most extra - solar planets are gas giants.
b. all stars feature nuclear fusion in their core.
c. all comets follow elliptical orbits.
d. all distant galaxies are moving away from us.

Explanation:

The Big - Bang theory suggests the universe originated from a singularity and has been expanding ever since. The observation that all distant galaxies are moving away from us (Hubble's law) is evidence of the universe's expansion, which supports the Big - Bang theory. Option A is about the composition of exoplanets, option B is about stellar processes, and option C is about the orbits of comets, none of which directly relate to the Big - Bang theory.

Answer:

D. All distant galaxies are moving away from us.