Yes Carbon dioxide is necessary for photosynthesis because Photosynthesis didn't go on because there was no Carbon dioxide in flask X.
The carbon dioxide was absorbed by the sodium hydroxide. In flask Y, the colour of the iodine solution turned blue black. This is because starch was present in the leaf of flask Y. Starch was present because it underwent photosynthesis.
 
        
             
        
        
        
To absorb nutrients and help us grow and to get rid of harmful bacteria
        
                    
             
        
        
        
Species have similar characteristics, but they are rarely, if not never, identical; the difference between them is variation!
Hope this helps! :) 
 
        
             
        
        
        
There you go! I hope it helped you :)
 
        
             
        
        
        
Answer:
A was the answer to mine but u didn't post your diagram so I don't know
Explanation: