Question

cosmic background radiation (cmb) is left over ______ from the initial expansion of energy in the universe.
options: wavelengths, dust, gamma, radiation

distant galaxies help us confirm that the universe is moving away from us by analyzing red shift. what characteristic of those galaxies allows us to use red shift for this evidence?
options: their size, the light they emit, the number of stars they contain, none of the above

Explanation:

First Question:

Cosmic background radiation (CMB) is leftover radiation from the early universe's energy expansion. Wavelengths are a property, dust is unrelated, gamma is a radiation type but CMB is leftover radiation.

Red shift is analyzed from the light galaxies emit (spectral lines shift). Size and star number don't relate to red shift. So the light they emit is the key.

Answer:

D. Radiation

Second Question: