Answer:
It would be (a)
Explanation:
A theory is something that can be proved through rigorous and repeated experimentation, while choice (b) sounds tempting i believe it fails at the fact that it says that a theory is an "agreement", sure an agreement could be reached by while trained scientists but that does not necessarily mean that what the scientists agree upon is rigorously tested and repeatable, and so therefore cannot be assumed
That is what I think
Hope this helps :)
Answer:
they stay shifted the same amount to the red
Explanation:
Redshift is given by

Where,
= Wavelength observed
= Wavelength emitted
Also
Transverse redshift is given by

v = Velocity of object
c = Speed of light = 
So, if the velocity is constant the redshift remains the same
Answer:
Amplitude and Frequency
Explanation:
Analog signals are composed of continuous waves that can have any values for frequency and amplitude. These waves are smooth and curved.
Radio transmissions are a combination of two kinds of waves: audio frequency waves that represent the sounds being transmitted and radio frequency waves that "carry" the audio information. All waves have a wavelength, an amplitude and a frequency as shown in the figure. These properties of the wave allow it to be modified to carry sound information.
The two most common types of modulation used in radio are amplitude modulation (AM) and frequency modulation (FM). Frequency modulation minimizes noise and provides greater fidelity than amplitude modulation, which is the older method of broadcasting . Both AM and FM are analog transmission systems, that is, they process sounds into continuously varying patterns of electrical signals which resemble sound waves.
I'd say diffraction since sound waves can bend around objects like corners. Let's say you're in the hallway and you can hear sound coming from a door. The sound waves diffract around the door and spread out into the hallway, making it possible for you to hear.
Also, you can hear it before you see it because light waves are shorter than sound waves and hardly diffract around doors.