The question has incorrect option, however the question can be answered by the general explanation. On the basis of the general explanation the answer is as follows:
Answer:
The correct answer is - Serine has a small side chain that can fit in any relatively polar environment.
Explanation:
Serine is an amino acid that have a small side chain in comparison of other amino acid and can be replaced by another amino acid with very least effect on the structure and function of a particular protein as they can fit in any relatively polar environment.
Serine have hydroxyl group in their side chain. It is polar amino acid that can easily establish itself in any polar condition and cause least changes in protein structure and function.
Thus, the correct answer is - Serine has a small side chain that can fit in any relatively polar environment.
 
        
             
        
        
        
The Earth's lithosphere is 100km while astehnosphere is 660km so this statement stands true. 
Other statements are false like Earth’s mantle is thinner than its oceanic crust as Earth’s mantle is around 3k km while its oceanic crust is just 5km. 
Also, Earth’s outer core is thicker than its mantle and Earth’s continental crust is thicker than its lithosphere is false as well.
        
                    
             
        
        
        
As both fill with liquid they expand. They are also both rounded shapes