What was the land, air and environment like during the precambrian time?

This came from my knowledge and I would like you to look at this and check to see if these information sounds familiar to you. 
Note: The Precambrian time was the earliest of the geologic ages.

Land: The land was marked by different layers of sedimentary rocks, with microscopic bacteria living in it. 
Air: The air was full of water vapors and CO2, which after time passed, turned into O2 through many chemical equations by photosynthesis. 
 Environment: Since the area was full of CO2 and water vapors, there were hardly any living creatures. I mean, if you count microscopic bacteria as a living creature, then I guess that could be part of a living organism.
This is all I know, and I hope this helped.

the answer to the blank provided is “an autosomal gene that is required for the expression of genes on the x chromosome”.

testis-determining factor, abbreviated as td, which is more popularly known as sex-determining region y or sry protein, is a dna-binding protein or  gene-regulatory protein/transcription factor, encoded by the  sry gene. it is the gene responsible for the initiation of male gender determination in humans.