A functional adaptation is any adaptation that helps an organism survive. 
Hence, the correct answer is option D - the color and shape of a flounder allow it to camouflage. 
This adaptation allows animals to camouflage with colors, patterns, and body shapes. Both predators and preys can process camouflage.
 
        
                    
             
        
        
        
C.
Hydrosphere refers to all the water on the earths surface therefore making C the only correct answer.
        
             
        
        
        
B I’m pretty sure still typing cause I need 20 letters