While Louis Pasteur was the one that procured the germ theory of disease that explains that diseases are caused by microorganisms, the first researcher that provided direct experimental data to support the said theory is Robert Koch. 
Robert Koch developed a criteria for the causality of disease from microorganisms called the Koch's postulates. The Koch's postulates indicate that:
(1) The bacteria must be present in every case of the disease
(2) <span>The bacteria must be extracted and isolated from the host with the disease and should be directly visualized and/or grown in culture
(3) There must be a healthy experimental host that will reproduce the disease once the isolated bacteria is injected
(4) The bacteria should be recoverable from the previously healthy host
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The monomers of DNA are called Nucleotides. They are made up of a 5-carbon sugar(deoxyribose), a phosphate group and a nitrogenous base bound to the sugar. Adenine makes two bonds with Thyamine whereas Cytosine makes three bonds with Guanine.
        
             
        
        
        
To absorb nutrients and help us grow and to get rid of harmful bacteria
        
                    
             
        
        
        
<h3>Answer:</h3>
c.   Using a combination of policy tools prevents the use of mandatory policies.
<h3>Explanation:</h3>
Regulating and controlling behavior is crucial for authorities. Authorities employ a number of tools such as enactment, penalties, laws, taxes, and support in order to change behavior in the concern of the people. The rising amount of policy difficulties has produced a difficulty for governments to control action. Moreover, conventional tools and methods in executing policy may be insufficient and ineffectual in circumstances of our current situation.