How do you scientist know that the universe is expanding

a the doppler effect shows stars with yellow shifted light
b the doppler. effect shows stars with blue light
c the doppler. effect shows stars with red shifted light
d the doppler effect shows stars with green light

B) The Doppler Effect shows stars with blue shifted light

one would be wind another would be water density

the relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell. reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.