About 4 billion years ago, Earth began to show signs of the conditions that allowed the first cells to take hold and populate ...

Were there already viruses on Earth when the first living cells appeared billions of years ago? – Aayush A., age 16, India How life on Earth started has puzzled scientists for a long time.

This study is published in the journal Nature. The first life forms to appear on Earth were unicellular, i.e. composed of a single cell, such as yeast or bacteria. Later, animals - multicellular ...