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 C. Over warm ocean water.
Warm water of the ocean bump into cold air.
        
             
        
        
        
By the ligand receptors on the surface of the cell membrane. How do transport proteins make it easier for certain molecules to diffuse across a membrane.  
the binding of a signaling molecule, or ligand, to its receiving molecule, or receptor.
 
        
             
        
        
        
By using a genetic diagram or a punnett square, we can show the the result of a cross between RR and rr.
The result of the genotypes should all be Rr.
This means all their offsprings should have the dominant trait being expressed.
Therefore, the percentage to this should be 100%.
The picture above is an example of using a punnett square finding the possible genotypes of the offsprings.
 
        
             
        
        
        
Answer:
Photosynthesis uses carbon dioxide to make sugar and produces oxygen as a byproduct. Respiration uses oxygen to release energy from stored sugar and produces carbon dioxide as a byproduct. ... However, if the plants are growing, then over a period of 24 hours they will produce more oxygen than they consume.