The answer for study island is genetic variation
        
             
        
        
        
Prokaryotic: has no nucleus, has no mitochondria. 
Eukaryotic: Has a nucleus, contain membrane bound organelles and divide through mitosis and meiosis
 
        
             
        
        
        
Answer:
Four abiotic forms of nitrogen cycle and its chemical formula 
Ammonium – 
Ammonia – 
Nitrite –  
Nitrate – 
Explanation:
Ammonium: In the nitrogen cycle ammonium is starting point that is present in soil and are converted to various forms by different process.
Ammonia: In the process of nitrogen fixation, the bacteria having nitrogenase enzymes reacts with the nitrogen as well as hydrogen and produces the ammonia, which is further converted to organic compounds. 
Nitrite: The nitrosomonas bacteria present helps in conversion of nitrogen gas into nitrite. 
Nitrate: Again the Nitrite is converted into Nitrate by the nitrobacter. During the process of assimilation ammonium and nitrate are absorbed by the plants.
 
        
             
        
        
        
Answer:
B
Explanation:
Both of the original DNA strands act as templates during replication. This option is correct. 
 
        
             
        
        
        
PH = - log [H+]
Transpose and solve for H+
3 = - log [H+]
H + =  

       =  0.001 M