It is the 
A. DNA molecules need to unwind before replication being
        
             
        
        
        
Answer:
Mutualism is a symbiotic relationship in which both species benefit. Commensalism is a symbiotic relationship in which one species benefits while the other species is not affected. Parasitism is a symbiotic relationship in which one species (the parasite) benefits while the other species (the host) is harmed.
 
        
             
        
        
        
Diabetes (type 2) is the resistance of insulin and is most commonly associated with hypertension and obesity
        
                    
             
        
        
        
Answer:  Low oxygen content.
Explanation:
There are many dangers to the survival of fish in shallow water that depend on the properties of water.
1. The oxygen content drops during the winter and also in hot weather. Fish cannot survive without enough oxygen in the water.
2. High evaporation rates can drain the pond.
3. Fortunately, water has a high thermal mass, so overheating the water to the boiling point is not an issue.
Of the three reasons given, lack of oxygen is the most critical.
        
             
        
        
        
Answer:
Avoid using killed vaccine for administration. 
Explanation:
Bruton's agammaglobulinemia may be defined as the X linked disorder that affects the immune system of an individual. This disease is mainly caused by the mutation in the gene responsible for coding the  Bruton tyrosine kinase.
The children suffering from this disease require special immunization and some precaution must be followed before immunizing them. These patients are not allowed to immunizes with the live vaccines as these vaccines can evoke the immune response strongly and child may get infected by the disease. The individual should not given immunosuppressive drugs or corticosteroids.
Thus, the answer is avoid using killed vaccine for administration.