Answer:
Closed Systems. The earth system as a whole is a closed system. ... Virtually no mass is exchanged between the Earth system and the rest of the universe (except for an occasional meteorite). However, energy in the form of solar radiation passes from the Sun, through the atmosphere to the surface.
Explanation:
If you conduct experiments and get consistent results and then change variables and again get consisnet results.
<em><u>Answer: Plasma.</u></em>
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<em><u>Explanation: Plasma is the liquid component of blood, in which the red blood cells, white blood cells, and platelets are suspended. It constitutes more than half of the blood's volume and consists mostly of water that contains dissolved salts (electrolytes) and proteins. The major protein in plasma is albumin.</u></em>
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Answer: A. before history was written.
Explanation:
I'm not sure if you need an explanation, but prehistoric means "very old or out of date." Hope this helps, Good luck! :)