It is A. Clay ....sand is not it
        
                    
             
        
        
        
With chromosomes crossing over frequently, it's more likely that genetic defects will occur in offsprinfg.
        
             
        
        
        
He used a simple microscope
        
             
        
        
        
Golden retrievers: loyal and playful family dogs
Pit bulls: bred for property guards and sadly dog fighting
German Shepard(K-9): good strength, sense of smell, speed, and stamina. Commonly used in the police force.
        
             
        
        
        
"The rotating part of the microscope at the bottom of the body tube; it holds the objectives." -utahscience.oremjr.alpine.k12.ut.us