B. CO2 levels in the atmosphere could increase and contribute to global warming problems.
 
        
                    
             
        
        
        
The four bases in DNA are: adenine, thymine, cytosine, guanine.
In RNA, thymine gets replaced by uracil. 
Purine is only a name for the two bases guanine and adenine. 
        
             
        
        
        
Answer:Ais the answer 
Explanation:
I passed biology last year and that’s something I remember 
 
        
             
        
        
        
It is probably the l<span>amellae.
The lamellae are sheets of bony matrix. This bony matrix is produced by o</span>steoblasts, which are cells that synthesise collagen<span> and specialised proteins like </span>osteocalcin<span> and </span>osteopontin. These are then the most important constituents of the bony matrix.