Plants deficient in nitrogen have thin, spindly stems and their growth is stunted.
        
             
        
        
        
The correct answer is differentiation.
Planetary differentiation can be defined as a process in which separation of different constituents of the planetary body takes place.They are separated based on their physical or chemical behavior, where the body divides into different layers: the less denser materials rise up to the surface and the more denser substance of the planet sinks.
Example: dwarf planets.
 
        
             
        
        
        
Sugar-phosphate backbone with the bases of the complementary base pairs adenine-thymine and guanine-cytosine projecting toward the inside of the backbone.
        
             
        
        
        
Different, because the old strands were not the same. The nucleotides of each strand of DNA are bonded together in a very specific way - it is called complementarity. 
For instance, one strand has a following sequence: ATTGACC . The other strand (or the new strand synthesised based on that strand) has complementary sequence: TAACTGG