C. Experimental
Explanation - The cause and effect of a process would be studied in experimental investigations. However, in descriptive studies, relationship between the factors are not studies rather the detail of the process is studied. In comparative investigation, several factors are compared and its effects are analyzed. 
In experimental investigations, experiments are carried out based on the hypothesis and then it is validated accordingly. Validation is a must to prove and disprove the hypothesis. Therefore, experimental data and hypothesis are related.
 
        
             
        
        
        
Answer:
B
Explanation:
that is the answer to the question 
 
        
                    
             
        
        
        
The answer is Convergence of images behind the Retina
Convex lens converges light to a principal focus. The thickness of the lens determines the focal length (distance between the center of the lens and the principal focal point). Therefore, by evaluating the thickness of the convex lens, farsightedness, (an eye defect of convergence of images behind the retina) can be corrected by enabling images in the eye to form behind the retina.
        
             
        
        
        
2 <span>different allele combinations would be found in the gametes produced by a pea plant who’s genotype was RrYY</span>