Answer:
a. the virus must be able to cross-link red blood cells directly. 
Explanation:
Viral hemagglutination assay is a method which is used for the quantification of the relative concentration of the viruses.
The principle on which the hemagglutination assay works is as follows:
- There are sialic acid receptors present on the surface of the red blood cells which will bind to the haemagglutinin glycoprotein present  on the surface of the viral particle. 
- Due to the binding of the sialic acid receptors with haemagglutinin particle there will be cross-linking of the red blood cells by the viral particles and a lattice formation will take place. 
- The lattice will remain suspended in the solution however if the concentration of the virus particles will be less, the lattice will settle down in the well. 
Thus, this method allows knowing the relative concentration of the virus. 
<em>Due to its basic principle of cross-linking this method works well for only a few viruses such as influenza virus. </em>
 
        
             
        
        
        
Red and white show incomplete dominance
Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely expressed over its paired allele. This results in a third phenotype in which the expressed physical trait is a combination of the phenotypes of both alleles.
Hope this helps! I'm happy to help with any other questions you might have :)
 
        
        
        
Absolute monarchy hold the supreme or absolute power, while in a constitutional monarchy the head of state is a hereditary or elected monarchy. in other words the king or queen of the absolute monarchy is a dictator.
        
             
        
        
        
Heat creates energy... the atoms move faster and faster, which changes the state of matter.
for example:
if a solid is heated, it turns to a liquid
if a liquid is heated, it turns to a gas
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Answer:
B
Explanation:
XX is female they produce eggs. XY is male. they produce sperm