This the respiratory system!
The major organ of the respiratory system is the lungs, and in the lungs the air gets divided among smaller and smaller tubes at the end of which the oxygen enters and carbon dioxide leaves the blood!
The answer is probably air.
<span>It took over 200 years for the "cell theory" to be formalized and accepted. Hooke and Leeuwenhoek were early microscopist's.... but at the time the nature of matter, the belief in spontaneous generation, and the idea there were little worlds within little worlds ad infinitinum was popular. The discovery of the periodic table and establishment that atoms were real, the demolishing of spontaneous generation, all happened at the time that Schwann and Schleiden (and others) were working with better microscopes, better ideas about the material world, and better observations...... thus the cell theory.
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Pretty sure its Ph scale i did a question like this once but i cant remember....its either Ph or richer
