Carbon is found in carbonate rocks, such as limestone, in the atmosphere as carbon dioxide gas, in water as dissolved carbon dioxide, and in all organisms as organic molecules, such as carbohydrates and nucleic acids.
Although these varying carbon-containing compounds exhibit different physical and chemical properties, their existence demonstrates
A.
the conservation of matter and energy.
B.
the dissipation of matter in an energy pyramid.
C.
the flow of energy through a food web.
D.
the differences in chemical reactions.