Question

first micro organisms on earth

Answer 1

Single-celled microorganisms were the first forms of life to develop on Earth, approximately 3–4 billion years ago. Further evolution was slow, and for about 3 billion years in the Precambrian eon, all organisms were microscopic. So, for most of the history of life on Earth, the only forms of life were microorganisms.

Answer 2

The ancestors of modern bacteria were unicellular organisms that werw the first form of life to appear on earth about 4 billion years ago.