At the smallest level of organization, the DNA wraps itself around small globular proteins called histones. Complexes of histones and DNA form nucleosomes, which appear as "beads" on the DNA strand. Chromatin refers to the decondensed DNA that has not formed separate chromosomes.
        
                    
             
        
        
        
“No man is an island.”This saying is also true for organisms in an ecosystem. No organism exists in isolation. Individual organisms live together in an ecosystem and depend on one another. In fact, they have many different types of interactions with each other, and many of these interactions are critical for their survival.
        
                    
             
        
        
        
Answer:
My guess would be an energy source, water, and an atmosphere.
Explanation:
Whatever lives there is going to need energy and water to survive. The atmospheric layer will protect the planet like ours protects Earth. Hope this helps! :)
 
        
             
        
        
        
Answer: Racial classification 
Explanation: Racial classification can be defined as the way humans are classified based on their physical and social traits which they have such as how they look, their skin color, hair texture, the native languages they speak. 
Scientists used racial classification to learn how unique and different humans are.