Hey pizzalover! The answer from this question would be
a. oxygen
Hope it helps
 
        
                    
             
        
        
        
Answer:
"
Natural gas does not produce greenhouse gases as other energy sources do."
Explanation:
The answer, "Coal deposits are found on nearly every continent and mining coal poses few risks." shows only how it can be a better option, but does not show how it can benefit. 
The answer, "Petroleum is relatively inexpensive compared to other forms of energy." only shows how it can be a better option, but does not show how it can benefit.
The answer, "Nuclear power increases water vapor in the atmosphere." does not clearly state how this benefits us.
<em>-kiniwih426</em>
 
        
             
        
        
        
Answer:
A. Carbon dioxide travels from the heart to the lungs in pulmonary arteries
Explanation:
 
        
             
        
        
        
Enzymes. There are 3 main types: Peptidase, Lipase, and amylase :) hope that helps! I'm learning that stuff too :)