3. Which of the following is most likely an observation of the Doppler effect that led to the discovery that the Universe is expanding?
a. When observed from a black hole, all of the stars in the Universe have
blueshifts.
b. The spectra of light given off by stars in the Milky Way Galaxy have
blueshifts,
c. When observed from Earth, light spectra from stars in other galaxies
have redshifts
d. The spectrum of light given off by the Sun has a redshift when it is
observed from Earth,

2points what is the job of a scientist? a. to answer ethical questions. b. to write laws based on his or her knowledge. c. to ask and answer scientific questions. d. to ignore facts that do not support his or her theory.

Plz mark brainliest 30 points 1) find the momentum of a 12 kg snowball that is rolling with a velocity of 9 m/s. 2) an 8 ball with a mass of .5 kg is sitting at rest. it is hit by the cue ball (1 kg) traveling at 2.5 m/s. if the cue ball is at rest after the collision, how fast is the 8 ball traveling after the collision? 3) two football players are running toward each other. if the offensive player is 75 kg and is running 8 m/s, how fast must the 60 kg defensive player run in order for the two players to hit and stop?

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules