The earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old. The signals consisted of a type of carbon molecule that is produced by living things.
the earliest life forms we know of were microscopic organisms (microbes) that left signals of their presence in rocks about 3.7 billion years old...the signals consisted of a type of carbon molecule that is produced by living things.
