Answer:
i think its C 
Explanation: im at the Beach all the time and waves wash the sand away 
 
        
             
        
        
        
Pure sodium can severely harm your body (toxic) which can lead to death
        
                    
             
        
        
        
Answer:
A. Mafic; iron and/or magnesium
Explanation:
Let's find the answer by naming some minerals and their chemistry.
Mafic minerals are dark-colored whereas felsic minerals are light-colored, thats way mafic rocks are dark-colored because they are mainly composed by mafic minerals and the other way around for felsic rocks.
But remember that mafic minerals as amphiboles, pyroxenes or biotites, involve in their chemical structure iron and/or magnesium. Although calcium and sodium can be incorporated in amphiboles and clinopyroxenes, they are not involved in orthopyroxenes and biotites. On the other hand, although potassium is involved in biotite and in some extent in amphiboles, this element is not involved in pyroxenes. 
So in conclusion, mafic minerals are usually dark-colored because they involve iron and/or magnesium in their chemical structures.   
 
        
             
        
        
        
Atoms are the smallest particales of an element that can take part in a chemical reaction. During a chemical reaction no particles are created or destroyed. The atoms are simply rearranged from the reactants to the products, mass is NEVER lost or gained in chemical reactions...Mass is ALWAYS conserved. :) Hope this helped