During a science class, Sarah observed that the Moon looked like a thin silver crescent in the sky. Her friend asked why the Moon's shape seems to change over time. Choose the correct reason.

Answer: D. Because different parts of the moon receive light from the sun at different times.

The Moon does not actually change its physical shape; it is always a sphere. We see "phases" because as the Moon orbits the Earth, the angle at which sunlight hits it changes from our perspective. This means we see different amounts of its sunlit half at different times.

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