Phases of the moon occur because
(a) we can see only that part of the moon which reflects light towards us.
(b) our distance from the moon keeps changing.
(c) the shadow of the Earth covers only a part of moon’s surface.
(d) the thickness of the moon’s atmosphere is not constant.
Answer
(a) we can see only that part of the moon which reflects light
Explanation
Moon does not produce its light, but reflects the light of the sun
Hence, we see only that part of the moon, from which the light of the Sun is reflected towards us.
