Answer:
I believe the answer is a single bacteria cell.
(I wrote to you more than three types)
There are seven known types of human coronavirus. Four common types (KHUI, OC43, NL63,229E) cause mild to moderate respiratory infection, such as the common cold. There are two types, severe acute respiratory syndrome (SARS-COV) and Middle East respiratory virus syndrome (MERS-COV), that can cause acute respiratory infections. Type VII (nCOV-2019) is the newly discovered novel coronavirus in China.
The fossils that provide information on the formation of an oxygen-rich atmosphere are the stromatilites from the Precambrian era. These are layered and columnar fossils consisting mainly of cyanobacteria which were the original life form back then. These bacteria took in carbon dioxide and produced oxygen by photosynthesis as early as 2.5 billion years ago (the earth is about 4.5 billion yrs old).
The answer is true I’m just guessing
