A voltaic cell spontaneously converts chemical energy to electrical energy. The correct option among all the options given in the question is option "2".
Actually voltaic cell is an electrochemical cell that
converts the chemical contained within it by the process of chemical reaction
to produce electrical energy. The voltaic cell contains an anode and a cathode.
Anode is an electrode where the oxidation occurs and cathode is the electrode
where reduction occurs. The oxidation and the reduction part occurs in two
separate parts of the cell known as half-cell.
        
             
        
        
        
The structure of 
Alanine is shown below,
Except the carbon atom of carbonyl group which is 
Sp² Hybridized, all remaining atoms are 
Sp³ Hybridized. The hybridization of each element is depicted in a box below,
 
        
        
        
I believe KI is not a a binary molecule.
Your welcome
        
             
        
        
        
Answer: My opinion is the second one because a lot of humans uses technology and technilogy replaces a lot of stuff.
Explanation: