Or, if you want the professor's technical explanation, "dye sensitised solar cells with titanium oxide layers on a surface with light absorbing dye molecules adsorbed on surface which can generate electricity".

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The result is a stamp of the posts that under a microscope looks like a sheet of bubble wrap, each covered with layers of electrolyte and the cobalt oxide anode.

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As the bacteria produced oxygen, the two compounds reacted to form iron oxide, which precipitated onto the seafloor in great layers of rust.

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