The importance of metals, particularly iron, and the importance of the discovery of metallurgy can hardly be exaggerated.
A key characteristic of life is active transport: control over what enters and exits the cell. Closer looks reveal exquisite “selectivity filters” with moving parts that make active transport work.
Walnut shells are found to create 3-D puzzles with tissues that even toothy squirrels can’t easily crack.
Astrobiologists think they may have found where life came from — cyanide in meteorites!