i believe the answer is b radioactive nucleotide
 
        
                    
             
        
        
        
Answer:
The answer should be C. 
An energy pyyramid shows how the energy "flows" from organism to organism as it goes up. 
 
        
                    
             
        
        
        
Answer:
Restriction enzymes (endonucleases) are used to cut the DNA into fragements.
Explanation
Restriction enzymes are obatained from bacteria where they are utilized by bacteria for protection against viruses. Restriction enzymes are used in biotechnology research. There are several restriction enzymes and each cut the DNA at specific site known as recognition site which is usually 4-8 neucleotide long. They produce sticky ends (cutting the both DNA strand on different site) and blunt ends (cutting the both DNA strand on same site) on DNA fragments. 
 
        
             
        
        
        
Carbon dioxide is not safe for your lungs because once it reaches your lungs it will stop your breathing and you could die.