A Multi-Celled organism has many cells (more than one). Examples would be plants, humans and animals/mammals. 
A Single-Celled organism only has one cell that makes up it's entire self. Examples would be bacteria and archaea. 
 
        
             
        
        
        
A observation and hypothesis
        
             
        
        
        
Answer:
D. by taking in oxygen and cleaning out waste gases like carbon dioxide.
Explanation:
The respiratory system cleans out your carbon dioxide and replaces it with oxygen.
 
        
                    
             
        
        
        
The correct answer is "C". 'Proton'. The number of protons is equal to the atomic numbers.
I hope this helps!
        
                    
             
        
        
        
Answer:
The last one  and the first one.
hope I could help you pls give this answer a hart thx
Explanation: