None, Electrons are not in the nucleus
<em>They</em><em> </em><em>are</em><em> </em><em>pres</em><em>ent</em><em> </em><em>in</em><em> </em><em>orbi</em><em>ts</em><em> </em><em>or</em><em> </em><em>ene</em><em>rgy</em><em> </em><em>shells</em><em>.</em><em> </em>
The skin plays a role in the production of vitamin D because when dehydrocholesterol reaches the skin by means of the blood and is exposed to ultraviolet light from the sun, it changes to vitamin D in an inactive form.
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Answer:
Hot air rises. Cool air comes rushing in to take its place.
Explanation:
<span>This is due to the higher forces needed to pump blood through the systemic circuit (around the body) compared to the pulmonary circuit.</span>