The best option is B He used a new experimental method to test his hypothesis. 
        
                    
             
        
        
        
Goods or services that are required.
        
                    
             
        
        
        
Answer:
Tartar.
Explanation:
Dental plaque may be defined as the development of mass or biofilm of bacteria that grows on teeth surface. This plaque may present on teeth, between the teeth and on teeth front.
The plaque is first colorless but when it changes to dental calculus or tartar, the color of plaque becomes yellow or pale brown. This causes dental problem and different dental disease.
Thus, the answer is plaque.
 
        
             
        
        
        
Answer:
1. How did the tidal wave  affect the predicted frequencies of the alleles in the population?
No changes
2. What is the frequency of the recessive allele?
q= 0.6
Explanation:
If we assume that all individuals were equally likely to be wiped out, that means the frequency/ratio of the gene and genotype of the population will not change. The tidal wave killing 100 out of 200, so it simply makes the population become half of it used to be.  
If the population at equilibrium, we can use the Hardy-Weinberg formula to find out the expected frequency of the dominant and recessive alleles. There are 36 homozygous recessives out of 100, so the frequency of the recessive allele will be:
q^2 = 36/100 
q= √36/100= 6/10= 0.6