Before revision: Thus life must be carbon based.The Unique Carbon Atom, National Oceanic and Atmospheric Administration, noaa.gov Fiction Speculations about the chemical structure and properties of hypothetical non-carbon-based life have been a recurring theme in science fiction.
After revision: Thus life must be carbon based.The Unique Carbon Atom, National Oceanic and Atmospheric Administration, URL Fiction Speculations about the chemical structure and properties of hypothetical non-carbon-based life have been a recurring theme in science fiction.