Answer:
The correct answer will be option-E
Explanation:
Hershey and Chase's experiment was performed to test whether DNA serves as the genetic material or protein.
To perform experiment they grew bacteriophage into radiolabeled phosphorus and sulfur compounds. The phosphorus is an integral part of the structure of DNA whereas proteins contain sulfur in their structure.  
In the given condition if radiolabeled nitrogen is utilized then the experiment will fail as the structure of proteins also contains an amino group( NH₂) in their structure as well as DNA. The scientist will not be able to identify whether the DNA is the genetic material or protein.
Thus, option-E is the correct answer.
 
        
             
        
        
        
Answer: Ligand gated channel
Explanation:
Ligand gated channel is an essential membrane protein that has pores and allows the passage of specific ions across the plasma membrane when it is activated by a specific chemical . Examples of such ions that pass through Ligand gated channels are Sodium ions, Potassium ions, Calcium ions. Ligand gated channels are found in extensions of the nerve cells. 
 
        
             
        
        
        
I think the answer may be D. But don’t answer yet, I may be wrong.
        
                    
             
        
        
        
C eastern Europe
Mostly near the baltics and the Balkans, but Czech is also a slavic language.
        
             
        
        
        
Inhaled nicotine is D. Absorbed and excreted rapidly