Answer:A habitat is the place where an organism lives while a niche is that organism's role within that environment.
Explanation:
 
        
                    
             
        
        
        
Ans: Cells are so small because it allows them to have a better surface area to volume ratio. This makes it much easier for the cell to bring in necessary nutreints and excrete wastes. Also the smaller the cell is, the less time it takes to replicate the small cell as opposed to a bigger cell.
        
             
        
        
        
Answer:
B
Explanation:
Proteins do store energy and nucleic acids provide energy thats why B is correct.
 
        
             
        
        
        
Answer:
<h3>Water creates pressure inside the cell that helps it maintain shape. ... Without water, cell membranes would lack structure, and without proper membrane structure, cells would be unable to keep important molecules inside the cell and harmful molecules outside the cell.</h3>
 
        
             
        
        
        
Answer:
To achieve precipitation of the DNA.
Explanation:
Isopropyl alcohol makes the DNA sediment. The DNA, once out of the solution, becomes visible, as it clumps. 
The result of adding isopropyl alcohol is the precipitation or sedimentation of DNA when DNA becomes like a visible thread with the help of alcohol and salt. The precipitation of DNA is important because it removes the dirt from DNA.