I believe it’s Precambrian.
        
                    
             
        
        
        
Answer:
The mentioned characteristics of variability are witnessed because of the phenomenon known as X chromosome inactivation in heterozygous females. As females possess two X chromosomes, they actually should not possess any color blindness.  
The phenomenon of X-chromosome inactivation takes place in a random manner at the time of embryo development. During this only one X chromosome is inactivated. If the chromosome comprising the defective gene is inactivated, the individual will possess normal vision.  
If the chromosome comprising the usual gene gets inactivated than the individual will be color blind. In the given case of female, X inactivation took place in one eye. The inactivation of normal alleles has taken place and thus she possesses normal vision with one eye and is color blind in the other eye.  
 
        
             
        
        
        
Fimbriae, flagella and pili are all examples of blank structures found in some bacteria.
        
             
        
        
        
The correct answer is 4.) Eventually they become separate species
A process of formation of a new species from an existing species is called speciation.
When a single species changed into two or more separate species, is called speciation. Speciation can take place due to reproductive isolation.  In reproductive isolation, the separated species no longer can interbreed among themselves. This is happened due to mating differences, sterility or environmental barriers which finally results into the adaptive splitting into two species.