D. get going 
the sentence is in the past
Carl explained to Mark that he had some work to do and had to go.
        
             
        
        
        
Here, the definition is given and asked for a word that is defined.
The rearrangement of atoms by breaking and reforming chemical bonds is called a chemical reaction.
Hence, "chemical" is the missing word. 
A <u>chemical</u> reaction is the rearrangement of atoms by breaking and reforming chemical bonds.
 
        
                    
             
        
        
        
Is there any answers to choose from?
        
             
        
        
        
So that way is there is a fire they can escape????
        
                    
             
        
        
        
On a job application, you should list all the following under "skills" except athletic interests. The answer is D.