Answer is 
body-brain barrier.
Explanation:
Mannitol injection is used to reduce swelling ande pressure around the brain.
It enhances flow of water from tissues including cerebrospinal fluid and the brain into plasma and interstitial fluid.
 
        
             
        
        
        
Answer:
When we look at reproduction too they are similar. They both produce gametes that fuse to form a zygote. They both have DNA that replicates to produce copies of itself.
 
        
             
        
        
        
Answer:
The difference in the given case indicates that the results are reliable but not accurate. Precision is the tendency of an apparatus to provide repeatable quantities, that is, inaccuracies are minor. The application of standard deviation is generally used as a precision error.  
Accuracy refers to the part of an apparatus that provides measures whose average is nearer to the accurate value. It is the reproducibility of an apparatus.  
 
        
             
        
        
        
Answer:
Many cells are specialized. They have structure that are adapted to their function. For eg : muscle cells bring parts of the body together. They contain protein fibres that can contract when energy is available, making the cells shorter.