The answer is C=genetic information flows from DNA to RNA to protein
        
                    
             
        
        
        
They were gigantic. Way bigger than a normal toroise
        
             
        
        
        
The answer is mutation
of genes.  The mutations were beneficial and gave the individuals of  the population
advantage and hence increased their survival. The classic features of birds
evolved one by one and gave birds advantage over their dinosaurs counterparts, especially the feature of small size.