Helicase "unzips" the two strands of DNA. During DNA replication.
        
                    
             
        
        
        
Answer:
The correct model is D.
Note: The first attachment below shows the different models. The second attachment shows the correct structural model of the water molecule.
Explanation:
A water molecule is composed of one atom of oxygen and two atoms of hydrogen.
A water molecule is polar, i.e. it contains positively and negatively opposite ends. The polar nature of the water molecule is due to strong electronegativity of oxygen which results in an uneven sharing of the bonding electrons between oxygen and hydrogen. The oxygen atom attracts the shared electrons more to itself, thereby, it acquires a partial negative charge, while the hydrogen atoms acquire a partial positive charge.
The bond angle between the oxygen and hydrogen atoms is approximately 105°. Therefore, from the first attachment below, the correct model for the water molecule is D.
 
        
             
        
        
        
Answer:
The correct answer is d Bill"s plasma contain B antibodies 
Explanation:
As Bill"s plasma contain B antibodies that"s why his blood cells do not aggutinate when mixed with anti B serum.
 
        
             
        
        
        
The only way to completely prevent Zika infection during pregnancy is to not travel to areas with risk of Zika and to use precautions or avoid sex with someone who has recently traveled to a risk area.