Question

how the earth formed ? how we organisms come on it?

Answer 1

I donot know the first part though

The first ever living organism on Earth was a bacteria known as cyanobacteria. It is believed by scientists that it first formed around 3 billion years ago. When the Earth was first formed, it was inhospitable for a long time until 3.8 billion years ago approximately, the core cooled down and the level of oxygen had risen. This, along with photosynthesis resulted in the formation of Cyanobacteria. These organisms were capable of carrying out the process of photosynthesis by which they prepared their own food. These were known as the common ancestors.