Answer:
Hmm, sorry, I do not think I have learned that yet.
 
        
             
        
        
        
Answer:
A 550
Explanation:
0.55 hectometers is equivalent to 550 decimeters.
 
        
             
        
        
        
Chloride and sodium, I believe. Chloride and Sodium are believed to be salty, and this concentration makes up 90% of all dissolved ions in the ocean.
        
             
        
        
        
Answer:
They all have cholorophyll 
Explanation:
Or we can say they carry out photodynthesis and make food. 
See, all the pictures are green, this green pigment (colour ) is cholorophyll.
The first, second and fourth are pictures of leaves [which makes food] and the third picture is a illustration of the mitochondria.
Hope it helps!