Answer:
Option (1), (2) and (3).
Explanation:
Doppler effect may be defined as the change in wavelength due to the the movement of sound or radiowaves travels from the object. The frequency remains same if the distance between the receiver and sender's electromagnetic wave distance is same.
Doppler effect helps to learn about the universe behavior. Hubble used the Doppler effect to study the velocity of galaxy. The galaxy motion can be indicated by the wavelength and light.
Thus, the correct answer is option (1), (2) and (3).
