Answer:
Using the concept of relative dating
Explanation:
Scientists use the concept of relative dating principles to determine when the Great Oxidation event occurred. 
Relative dating is the process of placing ancient event in their proper time sequence based on the relationship between rock lithologies. 
- An event like the great oxidation will have significant chemical, biological and physical effect on the rock units. 
- Rocks that form during this period in time will have very unique chemical signatures. 
- Therefore, by studying these rocks, the age of the layer can be fixed when we compare it to the standard geological column. 
 
        
             
        
        
        
Answer:
Increase the points, answers will pour in
Explanation:
nobody wants to answer tough questions for only 5 points. 
(please give brainliest)
 
        
             
        
        
        
Answer:
Pre B-cell is getting into checkpoint one, as it possesses a surrogate light chain that is adhered to its recombined heavy chain to make certain that the heavy chain is performing it's necessary duties. Cell is seen to be increasing in size as it undergo division into varying amount of small B-cells.