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A Trombe wall (Trombe rhymes with prom, by the way) is a wall that warms trapped air, and then circulates it to help heat a house. Trombe walls are ideally made out of a material with a fairly high thermal mass materials (like bricks or concrete), and are often painted black to improve heat conduction
<span>They are not visible because the chromatin coils up,shortens,and thickens.</span>
Compounds are made up of elements.
Elements are the ones we pull straight out from the periodic table.
For example:
H2O, HCl, NaCl, NaOH --> these are all compounds
H, N, B, Ne, Na, Cl, O, K --> these are all elements.
