Hello to answer your question.
A is correct
 But more likely forest fires would be the culprit because the trees produce O2
 so when the are burnt, it would be like everybody o this earth breathed out at   once causing CO2 to be released in to the atmostphere in a big burst
         Signed by, Virtuoso Sargedog
        
             
        
        
        
ok so no problem i’ll is going on the same page as ttyy and
        
             
        
        
        
No one you need to take care of yourself sis
        
                    
             
        
        
        
Answer:
The first step in the Scientific Method is to make objective observations. These observations are based on specific events that have already happened and can be verified by others as true or false. Step 2. Form a hypothesis.
Explanation: