Answer:
C, carbon dioxide and water
 
        
             
        
        
        
Anaerobic respiration is a function that can provide energy to organisms in place of, or in the absence of oxygen, so choice D. would be accurate.
        
             
        
        
        
Answer:
The Quantum Model of the Atom 1927
Explanation:
It is the most accurate model of the atom but I don't know about the easiest to visualise. Soz :(