Why does the Moon change shape?
The illuminated portion we can see changes.
The short answer
The Moon reflects sunlight. As it orbits Earth, we see different portions of its illuminated half. These are its phases: the object keeps its shape, but the bright portion visible from here changes.
An example to make sense of it
Ordinary phases are not caused by Earth’s shadow. That shadow is involved in lunar eclipses, a different phenomenon.
How to answer
Choose the conclusion best supported by the facts and press Check. You can revise an incorrect answer and use help whenever you wish.
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