Answer:
Replacing a lipid containing 18 C fatty acids with one containing 16 C fatty acids.
 
        
             
        
        
        
Answer:
Rain makes up part of earth's water cycle
Water evaporates from streams, lakes, and oceans, then condensation and precipitation occur in the form of rain. 
Explanation:
I'm pretty sure this question is implying that the answers should be directly related to the water cycle. While some of the other sentences might have some truth to them, they are too vague to be considered fact, and they're not necessarily related to the process of the water cycle.
 
        
             
        
        
        
Because it depends on the amount of humidity and perspiration produced in that area
        
             
        
        
        
D. flammability 
is a chemical property
        
             
        
        
        
<span>B. The enzyme amylase was saturated, as all its active sites were occupied by substrate starch.
Each enzyme molecule has an active site in which it binds to a substrate to complete the enzyme-substrate complex. This means that there has to be a balance of enzyme molecules to substrate molecules. </span>