Explain where the pericardium is found and what it does for the heart

Penelope studies how the structure and function of the nervous system is related to behavior. she is a psychologist

How can you tell the difference between rough er from smooth er?

What causes eclipses? check all that apply. earth's rotation on its axis moon's shadow covering the sun earth's shadow covering the moon earth's orbit and moon's orbit occasionally aligning the moon and sun's gravity pulling in the same direction