The Cambrian Period marks an important point in the history of life on Earth; it is the time when most of the major groups of animals first appear in the fossil record. This event is sometimes called the "Cambrian Explosion," because of the relatively short time over which this diversity of forms appears
        
             
        
        
        
Answer:
Gravitational forces.
Explanation:
The same reason the earth revolves around the sun, its all thanks to gravity!
-I hope this answers your question!
 
        
             
        
        
        
As DNA replication begins the DNA molecule is broken apart into two complementary strands. DNA replication is the process by which DNA makes a copy of itself during cell division. The process occurs in all living and is the basis for biological inheritance. The process starts with the separation of DNA strands in the double helix. Then replication for is formed followed by the binding of bases to each strand. Then the last step is termination of the Replication process