Elements in the first row (hydrogen and helium) will have outer electrons in the first energy level. Their principal quantum number is 1. Elements in the second row (lithium through neon) will have valence electrons in the second energy level with a principal quantum number of 2.
 
        
             
        
        
        
Answer: B
Explanation:
They inject their DNA into the cell, which reprograms that cell to become that virus. This is why viruses are so deadly and can spread throughout the body and to others easily, and efficiently. 
 
        
             
        
        
        
Answer:
the answers are c , d , and e 
Explanation:
 
        
                    
             
        
        
        
Burning fossil fuels and deforestation