Answer:
i think it's D
Explanation:
my bad if u get it wrong or anything
 
        
             
        
        
        
I’m not 100% sure what you are asking for but here is my explanation 
The grouping of objects helps the shopkeeper because now the shopkeeper can find where everyone is faster. This will ultimately make taking inventory easier. As a result the efficiency of the shop and the shopkeeper will be faster. An efficient shop will result in better sales and overall will make the shop better.
        
             
        
        
        
C. Agar provides a solid surface for bacterial growth.
Agar is a substance obtained from red algae which when added to a culture media, provides a solid surface for the growth of bacteria. When the agar is not added then the culture media remains as the broth and when the agar is added then the broth gets solidified. 
Agar is added 1.5-2% in the broth to get solidified. The growth of the bacteria depends on the amount of agar added. Agar is used for the growth of bacteria because it has gel like properties which holds the nutrients evenly and the bacteria can use it accordingly.
 
        
             
        
        
        
A biological system is a complex network of biologically relevant entities. ... Examples of biological systems at the macro scale are populations of organisms. On the organ and tissue scale in mammals and other animals, examples include the circulatory system, the respiratory system, and the nervous system. source: google