Answer; 
-Chitin is a structural carbohydrate that forms their exoskeleton
Explanation; 
-Chitin is the main component in the exoskeletons of arthropods and crustaceans and is also in the cell walls of fungi.
-It is a linear long chain polymer consisting of repeated units of N-acetyl-glucosamine. 
-The main function of the chitin-containing exoskeleton is to keep the inner soft tissue safe from any sort of injury and also prevents the delicate tissues from drying (acts as a water tight barrier against dehydration).
 
        
                    
             
        
        
        
A cell theory. 
Since cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
        
             
        
        
        
Answer:
To maintain the right body temperature, it is essential to have adequate body fat. Body fats are the storehouses of energy in the body. Body fats are necessary to ensure the smooth functioning of cells. Body fats have a cushioning effect on organs and tissues.
 
        
             
        
        
        
<span>This is speciation. In this process, two distinct species are formed through the intervention of some means such as differing environments or locations. This is done typically as a way of staying evolutionarily competitive in the area in which the species resides. The new species would be the exemplar of that which is best suited to the new conditions.</span>
        
                    
             
        
        
        
I am not totally sure but I think it’s B