Hello There!
Based on my First Aid classes the answer is D. All of the above.
If someone turns unconscious, you'd have to perform CPR and call an emergency service as soon as possible.
Hope This Helps You!
Good Luck :) 
- Hannah ❤
        
             
        
        
        
I Think The answer is a I hope it helps My friend
        
             
        
        
        
Answer:
True 
Explanation:
It can rapidly increase if the environment is good for them 
 
        
             
        
        
        
Answer:
The ocean produces oxygen through the plants (phytoplankton, kelp, and algal plankton) that live in it. These plants produce oxygen as a byproduct of photosynthesis, a process which converts carbon dioxide and sunlight into sugars the organism can use for energy.
Explanation:
hope it helps