<span>The molecules that provoke a specific immune response are called antigens.
</span>This molecule initiates the production of an antibody and causes an immune response. T<span>oxins, chemicals, bacteria, viruses, or other substances that come from outside the body can be part of the antigens.
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Answer:
So if the size of the pore is small then the rate of the diffusion will be very slow as the molecules will move from high concentration to low concentration in very slow rate.
Explanation:
I hope it helps you
 
        
             
        
        
        
Answer:
C) Flush out the contaminants with an excessive amount of water.
Explanation: 
Water is universal solvent. It dissolve many solutes inside it. Soil is contaminated with number of chemicals which is used by farmers for the controlling of pathogens. These chemicals remains on the soil for very long time. These chemicals are removed from the soil by applying high amount of water which flush out the chemicals from the soil. 
 
        
                    
             
        
        
        
PCR allows for the analysis of DNA fragments through the comparison of the base pairs each molecule contains, which can then be used for genetic screening and the identification of individuals and DNA fragments
        
             
        
        
        
No they cant be mechanical because then something would have to generate their rays through the inventing of a machine.