As the moon revolves around the earth, it also rotated on its axis why is that the same side of the moon is always visible from earth?

The answer is accually D.  The speed of the Moon's rotation keeps the same side always facing Earth.

Explanation:

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

that tool is called an altimeter which measures your altitude which can be used to tell which atmosphere you are currently in, including the stratosphere.

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