The level of DNA packaging which is brought about by the formation of nucleosomes it looks like beads on a string.
In general terms, nucleosomes are termed as a basic unit of DNA packaging which is in eukaryotes. 
It consists of eight segments of DNA wound. Nucleosomes form a fundamental unit which repeats the eukaryotic genomes to the nucleus by ensuring a well appropriate access to it.
        
                    
             
        
        
        
Answer:
I believe that it is D.
Explanation:
If ice caps are melting, and polar bears use the ice flows to get their food, then the polar bears can't use the ice to get food. so, the polar bears most likely are expanding their diets to adapt to their surroundings. So, polar bears are probably moving off the sea ice and eating other foods.