The answer is C, because covalent compounds can only form between those that are gases (at least at first)
        
             
        
        
        
Answer:
Atrioventricular valves.
Explanation:
Heart is the muscular organ of the body and acts as the pumping organ of the body. Human heart is not bigger than the fist and the human heart is divided into four chambers.
Heart murmur may be defined as the swishing sound that are made during the blood flow. This represent the heart problem. The bicuspid valve of heart is atrioventricular valve. The damage in the atrioventricular valve causes the heart murmuring.
Thus, the answer is atrioventricular valves.
 
        
             
        
        
        
Answer:
Apitite
Explanation: Apitite has a hardness of 5 it can scratch flouride but Quartz has a hardness of 7 meaning it can scratch Apitite
 
        
                    
             
        
        
        
It is the identity of the genes of your chromosomes that is your genetics that may not be physical, as compared to a phenotype which is a physical trait.