4. DNA
Not so much an invention as it is a discovery, nevertheless scientists have learned to manipulate it to our advantage. "We have discovered the secret of life," said British scientist Francis Crick in 1953, in reference to deoxyribose nucleic acid (DNA), the double-helix molecule in the cell nucleus that determines heredity.
Unraveling the genetic code has made it possible for humans to fight disease and improve food production while offering a deep understanding of our evolution.