What do we mean by redshift? Question 5 options: 1) A Doppler shift causing the observed wavelength to appear shorter than the emitted wavelength. 2) A Doppler shift caused by an object getting closer to the observer. 3) A Doppler shift caused by an object moving farther away from the observer. 4) A Doppler shift causing the observed frequency to appear higher than the emitted frequency. 5) A Doppler shift occurring only to the blue end of the visible band wavelengths. 6) A Doppler shift occurring only to the red end of the visible band of wavelengths