The discovery that most galaxies have red shifts implies that

implies that the universe is expanding.

By the doppler shift, you can have two shifts, the red implies that something is going further away from you, and a blue shift means that something is coming towards you. So the fact that most galaxies are getting further away, implies that there is a expansion occurring.

d

explanation:

i think the answer is d. but im not sure!

iron would move it is magnetic there is a mag field around the current in the wire